LIBRARY 

OF  THE 


MASSACHUSETTS 

AGRICULTURAL 

COLLEGE 


Source.       675 

B6 


4*\AXLis. 


I        '  9  1931 


THE 


CORRESPONDENCE   COLLEGE 
OF  AGRICULTURE 


FARM  ENGINEERING 

/ 

PART  I. 

FARM  STRUCTURAL  ENGINEERING 

BY 
H.  BOYDEN  BONEBRIGHT,  B.  S.  A.  Memb.  A.  S.  A.  E. 

Department  of  Agricultural  Engineering,  Montana  Agricultaral  College,  Bozeman,  Montana 


This  is  the  first  of  a  series  of  three  books  giving  a  complete  course  of  instruction  in 

FARM  ENGINEERING 


COPYRIGHT.     1911 

THE   CORRESPONDENCE  COLLEGE   OF   AGRICULTURE 

FORT  WAYNE.  INDIANA 


NOTE    TO    STUDENTS 


In  order  to  derive  the  utmost  possible  benefit  from  tiiis 
paper,  you  must  thoroughly  master  the  text.  While  it  is  not 
intended  that  you  commit  the  exact  words  of  the  text  to 
memory,  still  there  is  nothing  contained  in  the  text  which  is 
not  absolutely  essential  for  the  inteligent  farmer  to  know. 
For  your  own  good  never  refer  to  the  examination  questions 
until  you  have  finished  your  study  of  the  text.  By  follo"wing 
this  plan,  the  examination  paper  will  show  what  you  have 
learned  from  the  text. 

This  lesson  book  is  not  intended  to  be  a  "  book  of  plans ' ' 
for  farm  buildings. 

It  is  designed  to  give  in  a  practical  way,  the  funda- 
mental, scientific  knowledge  which  should  enable  the  student 
to  plan  farm  buildings,  which  will  exactly  fit  the  purpose 
for  which  they  are  built.  It  is  also  designed  with  a  view  to 
putting  the  student  into  closer  touch  with  the  Experiment 
Stations  and  the  Agricultural  Colleges,  that  he  may  derive 
therefrom  such  information  as  he  may  need  from  time  to 
time. 

No  attempt  has  been  made  to  repeat  information  which 
may  be  ohtained  for  the  asking,  from  the  Colleges  and  Ex- 
periment Stations. 

The  student  should  write  for  the  list  of  free  bulletins 
given  below  at  once,  in  order  that  he  may  get  them  in  time 
to  avoid  all  delays  in  his  studies. 


LIST  OF  FREE  BULLETINS— SEND  FOR  THEM. 

Bulletins  No.  100  and  117,  Agricultural  Experiment 
Station,  Iowa  State  College,  Ames,  Iowa. 

Farmers'  Bulletin  No.  3,  Montana  Experiment  Station, 
Bozeman,  Montana. 

Bulletin  No.  1,  Extension  Dept.,  Iowa  State  College, 
Ames,  Iowa. 

Sewage  Plants  for  Private  Houses,  Engineering  Ex- 
periment Station,  Iowa  State  College,  Ames,  Iowa. 


FARM  ENGINEERING 


PART  1 


DEVELOPMENT  OF  FARM  STRUCTURAL  ENaiNEERING. 

It  is  impossible  to  go  into  the  history  of  the  early  development 
of  farm  buildings  because  the  most  primitive-  of  men  had  rude  forms 
of  caves,  huts,  etc.,  which  served  as  a  protection  from  the  elements, 
from  savage  beasts  and  from  more  savage  men. 

In  fact,  within  the  last  century,  the  farm  buildings  in  many 
parts  of  the  United  States  were  usicd  as  shelters  for  man  and  beast 
and  as  forts  or  block  houses  to  protect  our  pioneers  from  the  Indians.. 
Some  of  the  buildings  are  still  in  use  in  the  Rocky  Mountain  region. 

Thus  we  see  that  military  influence  had  much  to  do  with  the 
early  development  of  our  farm  structures.  This  may  explain  to  some 
extent  the  heavy  framing  of  some  types  of  the  farm  buildings  of 
today. 

A  careful  investigation  is  not  necessary  to  prove  to  the  student 
of  modern  times  that  the  development  of  farm  structures  has  not 
kept  pace  with  the  marvelous  growth  and  development  of  city 
structures. 

The  needs  of  the  most  up-to-date  of  farmers  are  so  simple  when 
compared  with  the  needs,  of  a  great  manufacturing  concern  that  the 
designs  of  the  farm  buildings  are  comparatively  simple. 

This  fact  leads  in  too  many  cases  to  the  substitution  of  guess- 
work in  place  of  design.  The  inevitable  results  are;  unnecessary  ex- 
pense, a  lack  of  useful  qualities,  unsanitary,  inconvenient  and  un- 
sightly buildings  which  are  likely  to  last  but  a  short  time. 


1    #^'^^*'^'//^<*.-'*- 


Plates  1  and  2— SMALL  BARN  AND  POLE  SHED 

A  neat  little  barn  such  as  is  shown  in  Plate  1,  has  real  value  on  the  farm 
aside  from  its  usefulness  for  storage  purposes.  Its  attractiveness  adds  to 
the  value  of  the  farm. 

Such  a  "shack"  as  is  shown  in  Plate  2,  is  a  disgrace  to  anj^  farm,  and  its 
value  is  nearly  alwaj^s  a  minus  quantity. 


FARM  ENGINEBRINa.  5 

In  order  to  properly  understand  Farm  Structural  Engineering 
it  is  necessary  to  have  certain  parts  of  several  different  sciences  and 
arts  clearly  in  mind.     The  following  are  the  principal  sciences  and 


Plate  a-SEED  HOUSE 

A  cai'efully  desig-ned  seed  house  makes  an  excellent  building  in  which  to 
place   the   farm    office. 

arts  which  need  to  be  considered.     They  are  enumerated  alphabetic- 
ally, and  not  in  order  of  importance. 

*  Agronomy  *'*  Masonry. 

*  Animal  Husbandry.'  a.  Brick  masonry. 
**  Architecture  b.  Stone  masonry 
**  Carpentry  **  Painting 

**  Concrete  Construction  *  Poultry  Culture 

*  Farm  Management  *  Sanitary  Science. 

*  Horticulture 

"Wliile  it  is  impossible  to  take  up  all  of  these  subjects  completely, 
those  of  most  importance,  from  the  designer's  standpoint,  will  be 
treated  at  some  length. 

Agronomy. — The  seed  houses,  granaries,  hay  sheds,  corn  cribs, 
etc.,  should  be  designed  with  a  clear  understanding  of  the  require- 

*  Factors  governing  types  of  structures. 

**  Factors  directly  connected  with  the  actual  construction  of  the  structure. 


6  FARM  ENGINEERING. 

ments  of  each  building.  In  general  all  of  these  buildings  should  be 
well  ventilated.  In  most  eases  the  contents  of  the  building  require 
some  ventillation  and  in  all  cases  a  fair  supply  of  fresh  air  adds  to 
the  comfort  of  the  men  who  must  work  in  the  buildings.  The  seed 
houses  should  be  provided  with  plenty  of  light,  and  in'  the  colder 
climates  it  is  advisable  to  have  some  means  of  heating  the  work  room. 
On  large  ranches  the  seed  house  is  a  very  suitable  building  in 
M^hich  to  have  the  ranch  office. 

Animal  Husbandry. — In  order  to  design  the  barns,  stables,  hog 
houses,  silos,  etc.,  properly,  it  is  necessary  for  the  student  "to  have  a 
very  definite  understanding  of  the  requirements  of  the  live  stock. 

First,  it  is  commonly  conceded  that  all  live  stock  requirej^  ven- 
tilation. This  is  taken  up  under  each  different  plan  of  structure 
designed  for  the  housing  of  animals. 

Farm  Management. — If  the  designer  of  farm  structures  is  to 
work  intelligently,  he  must  know  where  and  how  his  buildings  are  to 
be  located.  He  must  also  know  the  relative  positions  of  the  other 
buildings. 

From  the  farm  management  standpoint  there  are  many  factors 
which  govern  the  location  of  the  farm  plant.  The  principal  points  are : 

Nearness  to  Farm  Land. — In  the  case  of  large  ranches  it  is  often 
advisable  to  place  the  buildings  as  near  the  center  of  the  land  as 
sanitary  conditions  will  permit.  Wliile  this  system  often  calls  for  a 
good  road  from  the  buildings  to  the  main  road,  the  extra  expense  is 
often  more  than  counterbalanced  by  the  time  which  is  saved  in  going 
to  and  from  the  fields. 

Nearness  to  Roads  and  Markets. — In  the  case  of  smaller  farms, 
care  should  be  taken  to  locate  the  buildings  as  near  to  the  market  as 
possible,  and  near  the  best  possible  thoroughfares.  In  case  a  distinct 
advantage  is  to  be  derived  by  locating  on  a  bad  road,  it  will  often  be 
found  profitable  to  improve  a  short  section  of  public  road  at  the  farm 
owner's  expense,  rather  than  to  locate  the  farm  building  in  A.n  un- 
desirable place.* 

Location  of  Buildings  With  Respect  to  Each  Other. — The  two 
systems  of  locating  farm  buildings  are  known  as :  First,  centralized 
plan;  Second,  distributed  plan. 

*  The  subject  of  road  building  and  Improvement    is    taken    up   in   another    book   of 
this   series. 


FARM  ENGINEERING.  7 

In  the  extreme  cases  of  the  central  plan,  the  dwelling,  the  stables 
and  out  buildings  are  all  under  one  roof.  In  some  parts  of  the  United 
States  such  farm  buildings  are  to  be  found  at  the  present  time.  In 
the  more  up-to-date  of  centralized  plans  the  house  is  separate  from 
the  other  buildings.  The  hogs  and  chickens  have  separate  houses  and 
the  horses,  sheep,  cattle,  grain,  hay  and  machinery  are  all  sheltered 
in  one  large  barn. 

The  distributed  plan  calls  for  separate  buildings  for  the  different 
species  of  farm  animals,  and  special  buildings  for  grain,  hay  and 
machinery.  In  many  cases  however,  the  necessary  grain  and  hay  is 
stored  in  each  of  the  buildings  which  shelters  animals.  Thus  in  some 
cases  the  granary  and  hayshed  are  eliminated  from  the  list. 

We  have  every  sort  of  variation  from  the  extreme  centralized 
plan  to  the  completely  distributed  plan.  As  the  designer  must  choose 
his  own  plan  of  location,  it  may  be  well  to  look  into  some  of  the  ad- 
vantages and  disadvantages  of  the  two  systems. 

The  centralized  plan  has  the  advantage,  in  that  feed  is  always 
handy  to  the  stock  to  which  it  is  to  be  fed.  Less  material  and  labor 
is  necessary  in  the  building  and  less  ground  is  taken  up  by  it. 

Its  disadvantages  lie  largely  in  the  danger  from  fire,  for  in  case 
a  large  farm  building  takes  fire,  it  is  almost  impossible  to  save  the 
building  or  its  contents. 

Again,  a  large  percentage  of  the  authorities  are  now  insisting 
that  the  different  species  of  live  stock  should  not  be  housed  in  the 
same  stables.  ,  . 

In  case  a  contagious  or  infectious  disease  gets  a  foothold  in  a 
large  centralized  plant  it  is  usually  very  hard  to  stamp  out.  A  case 
was  brought  to  the  attention  of  the  author  in  which  the  cost  of  clean- 
ing the  yards  and  an  old  fashioned  barn,  together  with  the  disinfect- 
ing after  a  siege  of  tuberculosis  cost  over  $1,700.00. 

The  Distributed  Plant. — The  smaller  barns  of  the  distributed 
plant,  are  easy  to  disinfect.  The  animals  of  different  species  are 
housed  in  separate  buildings.  In  case  one  of  these  buildings  burns  it 
is,  in  most  cases,  possible  to  save  the  other  buildings.  These  are  all 
distinct  advantages. 

The  cost  of  the  distributed  plant  is  somewhat  greater  on  account 
of  the  extra  amount  of  material  and  labor  required  to  construct  the 


8  FAEM  ENGINEERING". 

smaller  buildings.  More  of  the  farm  land  is  tak^n  up  by  the  build- 
ings as  they  are  usually  some  distance  apart  and  land  between  them 
is  seldom  cultivated. 

It  is  possible,  however,  for  the  man  who  is  starting  with  small 
capital  to  use  one  of  the  small  buildings  for  several  purposes  at  first 
and  later  add  such  buildings  as  may  be  necessary. 

With  these  points  clearly  in  mind  and  with  the  aid  of  a  thorough 
knowledge  of  the  different  agricultural  subjects,  the  student  may 
choose  intelligently  which  plan  is  best  suited  to  his  needs. 

Horticulture. — It  is  often  necessary  to  build  special  buildings 
for  the  purpose  of  storing  roots,  potatoes,  fruits,  cider,  etc.  The  con- 
struction of  these  buildings  will  differ  greatly  in  different  climates, 
but  the  general  principles  of  construction  should  govern  the  design 
of  all  buildings  for  horticultural  purposes. 


Plate  4-ROOT  CELLAR 

Root  cellars  must  be  designed  for  the  particular  conditions  which  prevail 
in  each  locality.     A  tjqDical  Greely*  potato  cellar  is  shown  in  Plate  4. 

Poultry  Culture. — Nearly  every  authority  on  poultry  has  some 
special  form  of  poultry  house  which  he  recommends  above  all  others. 
As  the  general  climatic  conditions  govern,  to  a  great  extent,  the  de- 
sign of  the  coops  and  houses  it  is  quite  impossible  to  make  a  single 
design  fit  all  conditions. 

Incubator  and  brooder  rooms  also  need  special  attention  as  a 
uniform  temperature  is  almost  necessary  in  these  apartments.     The 

*Greely,   Colorado,   is  noted  throughout  the  United   States  for  its  famous 
potatoes. 


FARM  ENGINEERING.  9 

detail  work  of  poultry  house  design  can  be  taken  up  to  better  advant- 
age in  connection  with  the  plans  of  the  various  buildings. 

SANITARY  SCIENCE. 

So  much  of  the  design  of  up-to-date  farm  structures  must  depend 
upon  sanitary  science  that  several  important  headings  must  be  taken 
up.  We  know  that  at  present  there  is  a  tendency  for  the  contagious 
diseases  of  man  and  beast  to  spread  rapidly  over  large  area.  This  is 
in  many  cases  because  the  conditions  under  which  the  animals  exist 
are  abnormal.  In  many  cases  even  the  lower  animals  abhor  these  con- 
ditions, but  they  are  so  confined  as  to  make  it  impossible  to  escape 
them.  The  structures  of  the  farm  should  be  so  built  as  to  promote  a 
natural,  healthy  existence,  not  only  in  the  lower  animals,  but  in  man  as 
well.  That  these  ends  may  be  accomplished  let  us  take  up  a  few  of 
the  most  important  sanitary  considerations. 

To  begin  with,  in  the  choice  of  a  building  site,  one  must  never 
overlook  the  sanitary  or  unsanitary  qualities  of  the  chosen  spot.  If 
the  desired  site  be  unsanitary,  and  this  condition  cannot  be  remedied, 
then  the  site  should  by  all  means  be  no  longer  considered  as  a  suit- 
able place  for  the  buildings.  Health  must  take  precedence  in  the 
choice  of  building"  sites. 

From  the  sanitary  standpoint  the  building  site  must  fulfill  the 
following  conditions : 

First :  The  slope  must  be  such  as  to  insure  surface  drainage  awau 
from  the  buildings  and  well.  In  the  very  level  'regions  it  is  some- 
times necessary  to  grade  up  the  building  site  to  some  extent.  If  what 
little  natural  drainage  there  is,  be  augmented  by  a  little  grad- 
ing it  is  often  possible  to  improve  the  sanitary  conditions  of  a  site  one 
hundred  per  cent. 

Second:  In  case  the  soil  is  of  such  a  nature  as  to  be  damp  or 
marshy  any  considerable  portion  of  the  year,  there  must  be  some  outlet 
into  which  sub-surface  drainage  may  be  emptied.  Tile  drains  should 
be  laid  so  as  to  thoroughly  drain  the  yards  and  the  soil  under  the 
different  buildings.  The  outlet  of  these  drains  should  be  located  so 
that  none  of  the  impure  drainage  water  can  possibly  get  to  the  well. 
It  should  never  be  used  as  drinking  water  for  the  farm  animals. 

In  case  the  buildings  are  located  on  a  steep  slope,  a  large  open 
ditch  should  pass  around  the  yards  above  the  building.     This  will 


10 


FARM  ENGINEERING. 


prevent  flood  water  from  running  into  the  yards,  buildings  and  wells. 
Make  the  ditch  large  enough  to  carry  away  the  water  of  a  flood,  not 
of  a  gentle  rain. 

Third:  Too  many  people  are  not  aware  of  the  fact  that  air 
drainage  is  just  as  essential  as  water  drainage.  A  site  for  the  farm 
buildings  is  often  chosen  in  a  deep  ravine,  or  in  a  dense  grove.  The 
currents  of  air  are  not  allowed  to  pass  about  the  buildings  and  yards, 
because  the  "wind  break"  is  too  dense.  There  should  be  a  free  cir^ 
culation  of  pure  air  about  all  the  buildings.  The  wind  dries  the 
damp  soil,  removes  the  noxious  odors,  and  helps  very  materially  in  the 
sanitation  of  the  farmstead. 

The  above  statement  must  not  be  taken  as  an  objection  to  wind 


Plate  5- SURFACE  WELL 

A  low  well  platform,  surrounded  by  mud  and  surmounted  by  chickens 
is  a  sure  sign  that  sickness  will  visit  those  who  must  drink  water  from 
the  well. 

breaks  or  to  trees.  Trees  are  essential  to  the  beauty  of  the  farms,  and 
Avlien  properly  arranged  aid,  rather  than  interfere  with  sanitation. 

Fourth :  Near  the  building  site  there  must  be  some  good  source 
of  pure  wholesome  water.  The  principal  source  of  farm  drinking 
water  is  the  farm  well. 

The  wells  may  be  classified  and  described  as  follows : 

Surface  Wells. — Those  wells  which  are  shallow  and  receive  their 
water  from  surface  drainage  are  called  surface  wells.  They  are  usual- 
ly unsanitary  because  the  surface  drainage  water  gathers  so  much 


FARM  ENGINEERING.  11 

filth  before  entering  the  well,  that  the  water  is  rendered  unwholesome 
and  dangerous. 

Shallow  Wells. — The  shallow  well  draws  its  water  from  sub- 
surface drainage,  and  often  in  times  of  flood  from  the  surface.  The 
shallow  well  does  not  receive  its  water  supply  from  beneath  a  layer 
which  is  impervious  to  water. 

The  shallow  well  has  to  be  placed  on  the  ' '  doubtful ' '  list  from  a 
sanitary  standpoint,  because,  although  the  water  may  be  pure,  it 
stands  a  chance  to  be  contaminated  with  dirt  and  disease  germs. 

The  Deep  Well. — The  deep  well  has  its  source  of  water  supply 
beneath  an  impervious  layer.  The  well  should  be  eased  water  tight 
from  the  curb  to  the  impervious  layer.  This  keeps  out  all  surface 
impurities.  While  the  water  of  such  a  well  may  contain  mineral  im- 
purities, it  is  almost  sure  to  be  free  from  disease  germs. 

Artesian  Wells. — The  artesian  well  is  a  "deep  well"  which  fur- 
nishes a  continual  or  intermittent  flow  of  water  without  the  use  of  a 
pump. 

Wells  may  be  further  classified  as  open,  bored,  drilled  and  driven.. 
In  general,  the  ground  about  the  well  should  be  higher  than  the  sur- 
rounding ground.    This  causes  surface  water  to  drain  away. 

The  casing,  whether  of  stone,  brick  or  steel  should  be  tight  to  a. 
point  several  feet  below  the  curb.  This  keeps  out  surface  water, 
small  animals,  such  as  mice,  rats  and  rabbits,  as  well  as  insects  and 
worms. 

Some  authorities  lay  down  the  rule  that  a  well  should  be  a  dist- 
ance equal  to  twice  its  depth  from  any  source  of  -contamination,  such 
as  privies,  cess  pools,  stables,  etc.  This  rule  is  in  general,  a  good  one,« 
but  in  some  instances,  the  distance  must  be  greater  than  twice  its. 
depth.  Again,  if  the  well  is  cased  water  tight  to  an  impervious  layer 
a  short  distance  beneath  the  surface,  it  is  not  always  necessary  to 
have  the  distance  to  sources  of  contamination  so  great. 

Spring's. — In  general,  springs  are  sources  of  pure  water.  But 
if  flood  waters  sweep  over  the  spring  occasionally,  there  is  great 
danger  of  contamination. 

The   farm  buildings  should   never  be   located  in   inconvenient, 


12 


FARM  ENGINEERING. 


A/yizr 


Plate  6- WELLS 

These  three  cross  sections  show  the  surface  well  (Fig.  1);  the  shallow 
well   (Fig.  2),  and  a  deep  well    (Fig.  3) 

The  dotted  arrows  show  the  points  where  the  water  supply  maj^  enter. 
Notice  the  sunken  condition  of  the  ground  about  the  surface  well.  Surface 
water,  insects  and  small   animals   can  enter  at  will. 

The  shallow  well  is  constructed  in  a  much  better  manner.  All  surface 
water  drains  away  from  the  top  of  the  well.  The  platforin  is  tight  and  the 
pump  fits  the  platform. 

The  deep  well  is  still  better.  It  is  cased  water-tight  down  to  the  slate, 
so  that  it  draws  all  its  water  from  below  the  layers  of  slate  and  stone.  Such  a 
well  may  always  be  considered  a  safe  source  of  drinking  water,  unless  by 
some  means  impurities  are  introduced  into  the  well  by  artificial  means. 

Dug  wells  may  be  cased  with  concrete  or  with  large  glazed  tiles  cemented 
at  the  joints.  Drilled  wells  are  cased  with  riveted  sheet  iron  tubing  or  with 
gas  pipe.     The  latter  is  the  better  by  far. 


FARM  ENGINEERING.  13 

unsanitary  places  just  because  of  a  spring.  The  water  should  be  piped 
to  a  good  location,  even  though  it  becomes  necessary  to  use  a  hydraulic 
ram. 

Streams. — In  mountain  regions  and  on  the  sparsely  settled 
plains  of  the  west,  it  is  often  possible  to  find  streams  which  are  safe 
sources  of  drinking  water.  In  the  thickly  settled  states,  however, 
this  is  seldom  the  case.  Under  these  conditions,  whenever  it  is  possible 
to  avoid  the  use  of  creek  or  river  water  for  drinking  purposes,  it 
should  always  be  done. 

After  the  site  has  been  chosen,  the  proper  drainage  systems  put 
in,  and  a  good  water  supply  established,  there  are  several  sanitary 
conveniences  which  are  indispensable. 

Sewage  Disposal. — The  common  system  of  disposing  of 
night  soil  upon  most  farms  is  by  the  old  privy  vault  method.  In 
general  this  system  is  to  be  condemned  as  filthy  and  very  unsanitary. 
It  is  possible  to  catch  the  night  soil  in  some  form  of  box  or  scraper 
and  haul  it  into  some  distant  field,  where  it  should  be  buried  at  once. 
In  case  it  is  not  buried  the  dogs  and  other  animals  are  likely  to  be- 
come covered  with  it  and  in  this  way  they  carry  disease  germs  fi'oni 
place  to  place.  In  case  quick  lime  is  added  to  the  soil  in  the  ssfiraper 
from  time  to  time  the  latter  method  is  found  to  be  fairly  satisfactory. 

Cess  Pools. — It  is  often  convenient  to  drain  the  sewage  from 
the  sinks,  bathtub  and  inside  closet  to  a  cess-pool.  If  the  cess-pool  be 
located  far  enough  from  the  well,  and  in  such  a  position  that  all  the 
drainage  is  from  the  tvell  toward ^tJie  cess-pool,  it  is  altogether  possible 
to  establish  a  sanitary  sewage  system. 

In  case  the  cess-pool  is  in  porous  soil,  it  is  seldom  necessary  to 
provided  an  outlet  drain.  The  seepage  is  usually  sufficient  to  provide 
ample  drainage. 

In  case  the  cess-pool  is  located  in  soil  which  is  impervious  to 
water,  it  sometimes  becomes  necessary  to  provide  a  drain  which  will 
carry  away  the  water  after  it  has  risen  to  a  height  of  from  four  to 
six  feet  from  the  top  of  the  cess-pool. 

The  sewage,  after  having  dropped  from  the  inlet  into  the  cess- 
pool moves  slowly,  and  in  consequence  allows  the  solid  portions  to 
settle  out.  The  remaining  fairly  clear  water  flows  out  of  the  drain. 
In  some  cases,  dams  are  placed  across  the  cess-pool  between  the  in- 


14 


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FARM  ENGINEERING.  15 

let  and  outlet.     The  dam  prevents  the  sewage  from  flowing  directly 
across  the  surface  of  the  water  and  out  of  the  drain. 

A  ventilator  should  always  be  provided  to  carry  off  all  noxious 
gases  from  the  cess-pool. 

The  Septic  Tank  and  Sewage  Disposal  Plants. — In  this  book, 
a  thorough  discussion  of  sewage  disposal  plants  is  impossible.  In 
general,  it  may  be  stated  that  the  sewage  is  carried  into  a  tank,  which 
should  be  dark  and  almost  unventilated.  The  contents  are  allowed 
to  stand  for  some  time. 

The  solid  matter  settles  out,  and  anaerobic  bacteria  decompose 
the  solid  part  of  the  sewage.* 

The  liquid,  teeming  with  billions  of  germs,  then  passes  out  and  is 
distributed  upon  filter  beds,  where  the  aerobic  bacteria  finish  the 
purifiying  process.  The  liquid  from  the  filter  beds  is  almost  pure 
water. 

So  many  theorists  have  written  exhaustive  articles  upon  the 
subject  of  private  sewage  disposal  plants,  that  the  student  is  likely 
to  become  confused,  unless  he  clearly  understands  the  whole  truth 
in  regard  to  these  plants. 

The  student  should  write  to  The  Iowa  State  College  Engineering 
Experiment  Station,  at  Ames,  Iowa,  for  the  bulletin  on  Sewage  Dis- 
posal Plants  for  Private  Houses. 

The  author  of  this  bulletin.  Professor  Marston,  (American  So- 
ciety of  Civil  Engineers)  is  an  authority  on  sewage  disposal  plants. 
No  Agricultural  library  is  complete  without  this^  bulletin. 

Blue  print  plans  are  furnished  by  Professor  Marston  to  those 
who  wish  to  build  plants. 

The  Cremating"  Pit. — A  great  many  ignorant  or  thoughtless 
farmers  drag  animals  which  have  died  of  contagious  diseases,  some 
distance  from  the  yards  and  leave  the  carcasses  to  decay,  and  be  eaten 
by  dogs  and  vultures. 

What  is  still  worse,  some  people  sell  the  carcasses  to  the  represen- 
tatives of  soap  factories.  Thus  the  germs  are  spread  wherever  the 
Avagon  load  of  carcasses  is  hauled. 

The  carcasses  should  be  removed  at  once,  to  a  cremating  pit  and 

*  Anaerobic  bacteria  work  when  oxygen  is    present    in   very    small    quantities,    if 
at  all.     Aerobic  bacteria  work  in  the  presence  of  oxygen. 


16 


FARM  ENGINEERING. 


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FARM  ENGINEEEING. 


17 


burned.  The  fire  destroys  all  germs,  and  tlius  all  possibilities  of 
other  animals  becoming  diseased  from  the  carcass  are  eliminated. 

In  case  the  cremating  pit  is  not  used,  the  carcasses  should  be 
removed  to  a  deep  grave  and  buried  in  quick  lime  which  will  destroy 
the  germs. 

However  a  cremating  pit  is  so  cheap  and  so  easy  to  build,  that  no 
up-to-date  farm  is  completely  equipped  without  one. 

The  Hospital  Stall. — The  hospital  stall  is  the  farm  "pest  house." 
It  should  be  so  located  that  all  drainage  from  it,  runs  away  from  the 
other  farm  buildings.  It  should  be  at  least  three  hundred  feet  from 
the  nearest  yards  in  which  uninfected  animals  are  kept.  On  the  small 
farm,  the  stall  may  be  built  to  accommodate  a  sick  horse  or  cow,  or 
several  sick  hogs  or  sheep. 


Plate  9— HOSPITAL  STALL 

A   hospital   stall    or   shed   costs   but   little,   but   it    is   often   the    means    of 
saving  many  hundreds  of  dollars. 


While  the  building  should  provide  protection  and  comfort  to  the 
patient,  it  should  easily  be  disinfected  throughout. 

As  soon  as  an  animal  is  dead  or  cured,  all  litter  from  the  stall 
should  be  buried,  and  the  stall  disinfected  inside  and  out  with  some 
powerful  disinfectant  such  as  crude  carbolic  acid  or  corrosive  sub- 
limate.   It  should  also  be  thoroughly  whitewashed  from  time  to  time. 


18  FARM  ENG  NEERING. 

Sanitary  Science  Governs  Building  Materials. — To  some  extent 
we  must  choose  our  materials  for  farm  buildings  from  a  sanitary 
standpoint.  The  materials  used  for  floors  and  sides  of  stalls  should 
be  impervious  to  moisture,  easily  cleaned,  and  strong  enough  not  to 
become  displaced. 

In  general,  the  material  and  workmanship  should  be  such  u.?  to 
produce  a  building  which  will  not  harbor  vermin,  which  will  be  strong 
and  which  will  be  easy  to  clean  and  disinfect. 

ARCHITECTURE. 

In  order  that  a  building  may  be  properly  constructed,  it  is  neces- 
sary to  have  the  parts  correctly  designed  from  two  standpoints. 

First :  From  the  standpoint  of  beauty.  No  man  can  lay  down 
rules  which  will  govern  all  the  proportions  of  a  building  from  the 
standpoint  of  beauty.    A  few  suggestions  are  offered  below. 

a.  Avoid  low,  "squatty"  buildings.  The  artistically  designed 
bungalow  is  an  exception  to  the  rule. 

b.  Sky-scrapers  appear  beautiful  in  a  city,  but  on  the  farm, 
high  buildings  which  cover  little  ground  are  unsightly.  They  are  also 
more    easily   blown    over. 

c.  Large  buildings  with  very  small  windows  are  likely  to  appear 
out  of  proportion. 

d.  A  small  barn  with  a  large  cupola  shows  poor  taste  on  the 
part  of  the  designer. 

e.  A  large  barn  should  never  be  fitted  with  very  small  cupolas. 
Use  ventilator  stacks.     They  do  not  appear  out  of  proportion. 

f.  The  cornice  of  a  building  should  project  at  least  as  many 
inches,  as  the  building  is  feet  high,  (from  ground  to  plate.) 

g.  Never  use  gaudy  paints  upon  farm  buildings.  They  are  un- 
sightly, and  usually  fade  quickly. 

h.  Remember  that  lean-tos  and  odd  shaped  out-buildings  detract 
much  from  the  symmetry  of  the  general  building  plan.  (See  Plates  10 
and  11.) 

Second :  The  more  important  consideratio.n  in  the  design  of  a 
farm  structure  is  strength.  The  'term  strength  is  too  often  miscon- 
strued to  mean  massiveness.  The  farm  architect  should  aim  to  com- 
bine real  strength  with  beauty.  He  must  know  that  the  crude  fasten- 
ing together  of  huge  timbers  does  not  always  indicate  strong   con- 


FARM  ENG INEERING. 


Plate  19 


Plate  11 
A  neat  little  open  feed  shed,  such  as  is  shown  in  Plate  10,  is  very  servic- 
able  and  looks  in  place  on  any  farm.     But  such  a  shed  as  is  shown  in  Plate 
11,  is  unsightly  wherever  it  may  be  located. 

struction.  In  farm  practice,  it  seldom  indicates  a  thorough  knowl- 
edge of  the  requirements  of  the  structure.  The  various  parts  of  the 
frames  of  structures  are  called  members. 

^Members  are  subjected  to  one  or  more  of  five  stresses. 

A.  Tension  is  the  stress  which  tends  to  pull  the  particles  of  n 
member  apart.  Example :  The  wires  of  a  telephone  line  are  sub- 
jected to  tension. 

B.  Compression  is  the  stress  which  tends  to  crush  the  particles 
or  molecules  of  a  body  together.  Example:  The  stones  in  a  wall  are 
subjected  to  compressive  stresses. 


20  FARM  ENGINEERINa. 

C.  Torsion  is  the  stress  which  tends  to  twist  a  member.  Ex- 
ample: A  screw  is  subjected  to  torsion  when  it  is  being  screwed  into 
a  piece  of  wood. 

D.  Bending  Stress.  When  a  member  is  subjected  to  transverse 
stresses  which  tend  to  bend  or  distort  it,  it  is  said  to  be  subjected  to 
bending  stress.  Example :  The  wagon  evener  is  subjected  to  bending 
stress. 

E.  Shear.  The  stress  known  as  shear,  tends  to  slip  the  mole- 
cules of  a  member  over  each  other.  Example:  Tin  is  subjected  to 
shearing  stress  when  cut  with  the  tin  snips  or  shears.  The  torsion  and 
shearing  stresses  do  not  enter  into  this  work  to  any  great  extent. 

In  taking  up  the  work  of  design,  we  shall  first  consider  the 
column.  No  part  of  the  farm  structure  receives  less  real  thought  than 
the  columns.  In  order  to  design  the  columns  correctly,  we  must  allow  a 
"factor  of  safety".  In  case  a  member  would  just  carry  a  certain  load, 
if  we  were  to  make  the  member  two,  three,  or  four  times  as  strong,  we 
would  be  using  the  factor  of  safety  of  two,  three,  or  four  respectively. 
The  factor  of  safety  must  be  determined  by  the  judgment  of  the 
designer. 

For  wood,  it  is  common  to  use  a  factor  of  four  or  more. 
For  steel  or  wrought  iron,  three  or  more. 
For  cast  iron  in  tension,  ten  or  more. 
For  cast  iron  in  compression,  six  or  more. 
For  good  stone  in  compression,  ten  or  more. 
For  poor  stone  in  compression,  very  large. 

Columns  are  divided  into  two  general  classes :  A,  short  columns ; 
B,  long  columns. 

A  short  column  is  shorter  than  ten  times  its  least  lateral  di- 
mension. Such  a  column  will  be  crushed  Avithout  bending  or  breaking. 
All  that  is  necessary  in  the  design  of  a  short  column  is  to  determine 
the  total  load  which  it  must  carry.  ]\Iultiply  this  by  the  factor  of 
safety,  divide  by  the  compressive  strength  of  the  material  in  the 
column.  This  will  give  the  number  of  square  inches  of  cross  section  of 
the  column. 

If  the  column  is  to  be  square,  simply  extract  the  square  root  of 
the  area  of  the  column,  and  choose  a  timber  x)f  that  dimension,  or  in 
ease  it  proves  to  be  an  odd  size,  choose  the  next  size  larger. 


FARM  ENG  INEERING.  21 

Example :  Design  a  soft  pine  column  three  feet  long  to  carry 
ten  tons  with  a  factor  of  safety  of  five,     (short  column.) 
10  tons  =  20,000  lbs.     20,000  lbs.  x  5  =  100,000  lbs. 
100,000    lbs.  -^  3000*=33y3.       The     square    root    of    33V3=5.7+ 
Use  a  6''x6'\    As  6  is  more  than  ^^  of  36",  the  column  is  "short." 

Th.  case  the  column  could  be  only  four  inches  thick,  then  we  would 
divide  33%  by  4.  Result,  81/3.  Use  a  4x10.  As  4  is.  more  than  jV 
of  "36,  this  colunm  is  also  a  "short  one." 

In  case  of  long  columns,  (columns  whose  length  is  more  than  tftn 
times  the  least  lateral  dimension)  it  is  common  to  use  a  special 
formula.  These  formulas  vary  greatly.  In  designing  columns  for  farm 
buildings,  it  is  seldom  necessary  to  apply  any  special  formula,  as  it  is 
nearly  always  possible  to  brace  the  columns  so  that  the  rule  for  short 
columns  applies.  In  general,  use  only  square  or  round  columns.  Use 
a  large  factory  of  safety,  and  be  sure  that  no  side  thrust  is  overlooked. 
In  case  the  column  receives  heavy  side  thrusts,  design  first  as  column, 
and  then  see  that  the  timber  is  strong  enough  to  bear  the  side  thrust 
by  the  use  of  the  rules  for  simple  beams. 

BEAMS. 

The  design  of  beams  is  much  harder  than  the  design  of  columns. 

Beams  are  divided  into  three  general  classes,  as  follows : 

Cantilever  Beams. — Those  beams  which  are  held  rigidly  at  one 
end  with  the  load  applied  at  the  free  end,  or  at  some  point  between 
the  fastening  and  the  free  end  are  termed  cantilever  beams.  (See  K 
and  A,  Plate  12.) 

Simple  Beams. — This  type  of  beam  is  supported  at  each  end 
and  the  load  is  applied  between  the  supports.  (See  B  and  C,  Plate  12.) 

The  Combined  Cantilever  and  Simple  Beam  in  which  the  beam  is 
rigidly  fastened  at  each  end  while  the  load  is  applied  between  the 
rigidly  fastened  ends. 

When  a  cantilever  beam  is  subjected  to  the  stress  of  a  weight, 
the  upper  part  of  the  beam  is  in  tension  while  the  lower  part  is  in 
compression.  At  some  point  between  the  top  and  bottom  of  the  beam 
there  is  a  point  at  which  there  is  neither  tension  nor  compression. 
This  point  is  the  neutral  axis. 

If  material  in  a  beam  is  placed  at  a  greater  distance  from  the 
neutral  axis,  the  beam  is  made  very  much  stronger. 

In  the  case  of  most  woods,  the  neutral  axis  is  near  the  center 
of  the  beam. 


22 


FARM  ENGINEERING. 


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Plate  12-BEAMS 


FAEM  ENGINEERING.  .  •      23 

In  case  a  4x8  is  laid  upon  its  side,  the  greatest  distance  that 

.  any  of  the  Avood  is  from  the  neutral  axis  is  about  two  inches.  While 

if  the  beam  is  placed  upon  edge,  the  greatest  distance  is  four  inches.. 

The  average  distance  in  the  first  case  is  one  inch,  and  in  the  latter  case 

it  is  two  inches. 

As  the  strength  of  a  beam  depends  upon  the  distance  Avhich  the 
material  is  from  the  neutral  axis,  we  find:  Rule  1.  The  strength  of 
a  beam  varies  as  the  square  of  its  depth. 

As  the  leverage  of  a  beam  varies  directly  as  the  length,  we  ob- 
tain the  following  rule.  Rule  2.  The  strength  of  a  beam  varies 
inversely  as  its  length. 

Rule  3.     The  strength  of  a  beam  varies  directl}^  as  it  thickens. 

By  using  the  above  rules  in  connection  with  table  2,  the  strength 
of  an  ordinary  beam  can  be  easily  determined.  (Fig.  B,  Plate  12,  is 
loaded  with  concentrated  load,  W.  Fig.  C,  Plate  12,  is  loaded  with 
distributed  load,  such  as  hay,  grain,  etc.) 

In  Fig.  D,  Plate  12,  the  rod  n  P  m  is  called  a  truss  rod.  The 
beam  nm,  is  designed  as  a  column  first,  later  it  is  designed  as  a  beam, 
the  length  being  the  distance  from  the  center  of  the  strut  S,  to  the 
points  n  or  m-.    The  rod  must  carry  all  of  the  load. 

Never  use  more  than  two  struts  between  a  beam  and  a  rod. 

The  trussed  beams  are  not  very  common  in  farm  buildings. 

Rafters  are  designed  as  beams,  with  this  exception ;  the  beam  is 
considered  to  be  the  length  of  the  run  of  the  rafters,  not  the  length 
of  the  rafter  itself.  A  very  large  factor  of  safety  must  be  allowed  on 
account  of  the  wind  which  exerts  terrific  force  upon  the  roofs  of 
buildings  in  some  localities. 

TABLE  1. 
SAFE  STRENGTH  OF  MATERIAL  IN  POUNDS  PER  SQUARE 
INCH  OF  CROSS  SECTION. 
MATERIAL  COMPRESSION  ' 

•  Brick  (in  cement)  200  lbs. 

Brick  (in  lime)  75  to  125  lbs. 

Good  Granite  500  lbs. 

Good  Limestone  -^00  lbs. 

Rubble  Work  (in  lime)  100  lbs. 

Concrete  (one  part  cement,  two 
parts  sand,  clean  and  sharp, 
two  parts  gravel,  clean  and 
rough.  150  lbs. 


24 


FARM  ENGINEERING. 


MATERIAL  COMPRESSION  TENSION 

Yellow  Pine  1,000  lbs.  lengthwise  2,000  lbs.  lengthwise 

125  lbs.  crosswise         crosswise 

Wrought  Iron  10,000  lbs.  10,000  lbs. 

Cast  Iron  2,000  lbs.  1,000  lbs. 

White  pine  is  about  %  as  strong  as  yellow  pine. 

Hemlock  is  about  %  as  strong  as  yellow  pine. 

Oak  is  about  as  strong  as  yellow  pine. 

TABLE  2. 
BEST  YELLOW  PINE  BEAMS. 

In  the  following  table  the  beam  is  considered  to  be  one  full  inch 
thick,  and  free  from  knots,  holes,  etc. 

The  loads  are  safe  for  perfect  beams  only. 

To  compute  the  strength  of  a  2x4,  one  would  have  to  remember 
that  a  stock  2x4  is  only  li/o  inches  thick.  Consequently,  multiply 
by  1V2-    If  there  are  any  knots  make  allowance  for  them. 

The  table  is  made  for  uniformly  loaded  beams.  See  Fig.  C, 
Plate  12. 

For  beams  with  concentrated  load,  divide  the  figures  of  the  table 
by  two,  (2).  ■ 

For  cantilever  beams  uniformly  loaded,  divide  by  four,  (4). 

For  cantilever  beams  with  load  at  the  outer  end,  divide  by  eight 
(8). 

Width  of  beam  1  inch.  (Full  inch.) 


Depth  of 
beam 
in  inches 

Length  of  beam  in  feet 

6 

8 

10 

12 

14 

16 

18 

2 

150 

120 

4 

600 

480 

380 

300 

6 

1400 

1080 

850 

700 

600 

490 

8 

2500 

1920 

1500 

1250 

1100 

960 

10 

4000 

3000 

2400 

2000 

1700 

1500 

1300 

12 

4300 

3400 

2800 

2450 

2150 

1900 

14 

3900 

3300 

2900 

2500 

White  pine  is  about  %  as  strong  as  yellow  pine. 
Hemlock  is  about  %  as  strong  as  yellow  pine. 
Oak  is  about  as  strong  as  yellow  pine. 
Spruce  is  about  %  as  strong  as  yellow  pine. 


FARM  ENGINEERING^.  25 

TABLE  3 
LOADS. 

The  following  table  gives  the  weights  of  the  different  materials 
per  square  foot.  In  case  of  roofs,  the  square  foot  of  roof  surface 
(not  horizontal  surface)  is  used. 

MATERIAL.  ^^^^^^'^  ^^l^oT^'"''' 

%-in.  Sheathing  2  to  2  lbs. 

Lath  and  Plaster  7  to  10  lbs. 

Shingles  2  lbs. 

1-Inch  Flooring  About  4  lbs. 

Oats  22  to  25  lbs.  per  foot  in  depth. 

Corn  40  lbs.  per  foot  in  depth. 

Barley  35  lbs.  per  foot  in  depth. 

Wheat.  40  to  45  lbs.  per  foot  in  depth. 

Hay,  (loose)  4  to  5  lbs.  per  foot  in  depth. 

Hay,  (bales)  15  to  25  Jbs.  per  foot  in  depth. 

Table  of  cubic  feet  of  space  needed  for  different  animals. 

A  horse 600  to  800  cubic  feet. 

A  cow 500  to  600  cubic  feet. 

A  hog 150  to  300  cubic  feet 

A  sheep    150  cubic  feet. 

A  hen 15  to  25  cubic  feet. 

The  above  is  merely  an  estimate  and  does  not  have  to  be  ad- 
hered to  strictly. 

MECHANICAL  DRAWING. 
The  student  does  not  need  to  be  an  "  artist ' '  at  mechanical  draw- 
ing.   He  should,  however,  be  able  to  express  his  thoughts  by  means  of 
drawings.     The  necessary  instruments  and  equipment  are: 

Drawing  Board. — A  flat  board  12''  by  14".  A  larger  board  is 
often  desirable  for  larger  drawings. 

"T"  Square.— A  flat,  thin,  straight  edge  fastened  at  right  angles 
to  a  short  thick  piece  of  wood  (%'''x2''').  The  "T"  square  is  placed 
with  the  cross  piece  against  the  end  of  the  drawing  board  and  all 
horizontal  lines  are  drawn  along  its  upper  edge. 

The  Triangles — The  triangles  are  usually  made  of  hard  rubber  or 
celluloid.     To  draw  perpendicular  lines  place  the  triangle  upon  the 


26  FARM  ENGINEERING. 

"  T  "  square  and  draw  lines  along  the  edge  of  the  triangle.  Triangles 
usually  have  one  right  angle  and  two  angles  of  45  degrees. 'The  latter 
angles  on  some  triangles  are  60  degrees  and  30  degrees.  A  ''45  de- 
gree triangle"  is  sufficient  for  this  work. 

Right  Line  Pen. — The  blades  of  a  right  line  pen  can  be  adjusted 
to  any  width  of  line  which  the  draftsman  wishes  to  use.  In  most 
cases  a  pencil  drawing  is  all  that  is  necessary  for  the  farm  build- 
ings. 

Dividers. — The  ordinary  dividers  are  so  made  that  either  pen  or 
pencil  may  be  fitted  into  them.     They  are  used  for  drawing  circles. 

Scale. — The  Scale  is  often  called  a  "rule."  The  "Mechanical 
triangular"  scale  is  suited  for  this  work.  The  inches  are  divide'd 
into  %,  1/4,  Vs,  etc.,  whereas  in  the  engineer's  scale  the  inches  are 
divided  into  tenths. 

The  outlines  of  a  structure  should  be  shown  in  heavy  solid  lines. 
Any  part  inside  the  building  which  could  not  be  seen  from  the  outside 
may  be  put  in  in  dotted  lines.  In  some  cases  a  portion  of  the  outside 
may  be  "cut  away"  and  the  framing  shown  in  light  solid  lines  .(See 
individual  hog  house.) 

The  student  should  draAv  each  floor,  the  roof,  and  at  least  one 
view  of  a  side  and  an  end.  For  correct  system  of  drawing  see  plate 
of  machinery  shed.  Never  try  to  draw  perspective  drawings  such 
as  is  shown  in  the  lower  figure  of  the  individual  hog  house.  They 
are  difficult  to  make  and  they  are  satisfactory  only  for  those  who 
cannot  understand  mechanical  drawing  of  the  ordinary  kind. 

Dimension  lines  should  be  supplied  wherever  necessary.  They 
are  light,  solid  lines  with  arrows  at  each  end,  showing  the  exact  ter- 
mination of  the  line.  Feet  and  inches  are  placed  near  the  middle  of 
the  line.  8'  indicates  eight  feet,  while  8''  indicates  eight  inches.  ?' 
6^'  is  the  mechanical  way  of  writing  three  feet  six  inches. 

EXCAVATION. 

In  case  it  becomes  necessary  to  remove  earth  or  stone  in  order 
to  locate  the  foundation  of  a  building,  the  student  should  understand 
the  system  of  laying  out  the  work.  He  should  also  know  how  to 
estimate  the  quantity  of  material  which  must  be  moved. 

The   lines   of  the   excavation      should  be   at  least  three  inches 


FARM  ENGINEERING.  27 

outside  of   the  side  line  of  the  Avail.     The  space  between  wall  and 
natural  earth  is.  filled  in  with  sand,  gravel  or  earth. 

The  quantity  of  material  to  be  removed  is  estimated  in  cubic 
yards. 

It  is  often  cheaper  to  excavate  a  runway  at  one  side  or  end  of 
a  basement  in  order  to  allow  the  use  of  teams  and  scrapers  in  place 
of  hand  labor. 

The  estimating-  of  such  work  is  very  easy. 

Example. — Find  the  number  of  cubic  yards  of  earth  to  be  re- 
moved for  a  basement  33'x64'.    Average  depth,  4  feet. 

(In  this' case  a  team  and  scraper  should  be  used.  The  runway 
would  be  about  eight  feet  wide  and  ten  feet  long.) 

Body  of  excavation:  32'  plus  6"=32.5'.  64'  plus  '^=64.5' 
64.5'X32.5'X4'=8,424  cubic  feet.  8,424  cubic  feet  ^  27=312  cubic 
yards.     (27  cubic  feet=:=l  cubic  yard.) 

Runway  excavation:   ( 2'= average  depth  of  runway.) 

10'x2'x8'=160  cubic  feet-f-27=5.9  cubic  yards.  (6  cubic  yards.) 

Total,  312  cubic  yards  plus  6  cubic  yards  equals  318  cubic  yards. 

MASONRY. 

While  a  large  book  might  be  written  on  the  subject  of  masonry, 
a  few  simple  statements  will  give  the  student  a  clear  understanding 
of  the  points  to  be  observed. 

In  both  brick  and  stone  work,  the  walls  should  have  all  joints 
broken.  In  Plate  13,  J?  indicates  "Rubble"  stone  work  wdth  the 
joints  properly  broken;  r  is  a  wall  of  the  same  type  with  the  joints 
improperly  broken  at  the  points  indicated  by  arrows. 

C  and  c  represent  properly  and  improperly  laid  walls  of  "Course 
work." 

B  and  b  show  properly  and  improperly  laid  brick  walls. 

All  walls  should  be  "bonded"  by  means  of  stone  or  bricks  which 
join  the  outer  and  inner  layers  of  the  wall.  In  case  of  brick  w^ork, 
the  layers  of  "bonding  brick"  should  not  be  more  than  seven  layers 
apart. 

Fig.  N  of  Plate  13,  shows  a  top  view  of  a  16-incli  brick  wall 
bonded  with  ordinary  brick. 


28 


FARM  ENGINEERING. 


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I.  .'■'■■    ■■ 


«       i 


?=F^ 


T— r 


-A\'!'.i,',|.',;;,',','.'.|.',i.M^>^        i;  !;■  \\  \\  :\  ;!^ 


/k 


1    1    1    1    1 

1    1    1    1 

1    1    1    1    1 

1    1    1    1 

1 

>v 


i^iavTg 


naz 


2^ 


sz 


Plate  13-WALLS 


FARM  ENGINEERING.  29 

■  Fig.  M,  Plate  13,  shows  a  special  type  of  invisible  bonding  brick. 
Strips  of  iron  with  hooked  ends  are  sometimes  used  for  bonding  pur- 
poses. 

In  case  walls  do  not  cover  sufficient  ground  to  carry  the  weight, 
the  bottom  of  the  wall  is  made  wider  in  order  to  increase  the  bear- 
ing surface.  The  extension  at  the  foot  of  the  wall  is  called  a  "Foot- 
ing." 

Fig.  X,  Plate  13,  shows  a  concrete  wall  with  footing. 

Fig.  Z,  Plate  13,  is  a  tapered  wall  which  gives  the  desired  re- 
sults in  many  cases.  The  openings  for  all  doors  and  windows  should 
be  arched,  or  provided  with  a  stone  cap."  The  cap  should  be  of  ample 
size  and  should  extend  out  into  the  walls  far  enough  to  have  ample 
bearing  surface. 

All  angles  of  a  cement  or  concrete  wall  should  be  rounded  and 
the  wall  reinforced  at  the  angle  to  prevent  cracking. 

Mortar. — Lime  mortar  consists  of  calcium  oxide  (quick  lime) 
which  has  been  slacked  in  sufficient  water  to  make  a  thick  paste. 
The  paste,  when  mixed  with  sand  and  exposed  to  air  takes  up  carbon 
dioxide  and  becomes  limestone. 

As  limestone  is  soluble  in  water  containing  carbon  dioxide,  the 
lime  mortar  is  subject  to  rapid  disintegration.  It  is,  however,  cheap 
and  very  satisfactory  for  rough  work.  Most  farm  houses  are  plastered 
with  lime  mortar,  the  first  coat  containing  plastering  hair,  the 
second  coat  containing  no  hair,  and  the  third  coat,  (in  case  one  is 
applied)  being  made  of  nearly  clear  lime  plaster. 

Cement  mortar  is  made  of  cement  and  sand.  When  the  cement 
takes  up  water,  it  recrystallizes  and  forms  stone.  The  mortar  re- 
quires plenty  of  moisture  for  the  completion  of  the  setting  process. 
As  the  cement  mortar  is  very  hard  and  insoluble,  it  is  preferred  for 
outside  work  and  for  "Pointing  up"  walls. 

"Pointing  up"  consists  of  digging  out  all  loose  mortar  at  the 
outer  edge  of  the  joints  and  completely,  filling  in  the  joint  with  mortar. 
The  mortar,  when  rounded  with  a  special  trowel  is  said  to  be 
"beaded." 

CARPENTRY- 

Several  volumes  of  very  good  material  have  been  written  on  the 
subject  of  carpentry.* 

*  "The  Steel  Square,"  by  Fred.  T.  Hodgson,  and  "The  Builder  and  Wood  Work- 
er," tay  F.  T.  Hodgson,  are  published  by  Sargent  &  Co.,  94  Center  Street, 
New  York.  / 


30  FARM  ENGINEERING. 

The  day  of  the  "old  fashioned"  carpenter  who  spent  much  time 
putting  in  complicated  sill  joints,  and  numberless  mortices  is, nearly 
past.  The  increase  in  the  price  of  lumber,  and  the  enlightenment 
of  the  designers  have  reduced  the  size  of  the  timber  a  great  deal. 
This  makes  it  imperative  that  all  unneceessary  mortices  should  be 
done  away  Math.  Consequently,  the  joints  of  up-to-date  farm  build- 
ings are  now  almost  exclusively  held  together  by  spikes.  The  free  use 
of  spikes  in  the  proper  places,  proves  to  be  a  great  help  in  securing 
strength  and  rigidity  in  our  buildings. 

The  pitches  of  .roofs  and  the  length  of  rafters  are  considered  by 
many  to  be  hard  problems  for  the  amateur  carpenter. 

,  The  common  system  of  computing  pitches  is  by  number  of  inches 
which  the  rafter  rises  in  passing  over  one  foot  of  horizontal  distance. 

The  distance  the  rafter  rises  in  passing  over  one  foot  of  surface, 
is. termed  the  "Rise".  The  horizontal  distance  over  which  it  passes 
is  termed  the  "Run".  ■ 

The  pitch  is  named  according  to  the  fraction  of  the  total  width 
of  the  building  which  the  regular  gable  roof  rises  above  the  level  of 
the  plate. 

Example. — On  a  building  twelve  feet  wide^  if  the  gable  were 
three  feet  above  the  plate,  the  pitch  would-be  14.  (6"  rise  to  1  ft.  run). 
If  .the  gable  were  4;  feet  above  the  plate,  the  pitch  Avould  be  %.  (8" 
rise  to  1  foot  run.)  If  the  gable  were  6  feet  above  the  plate,  the  pitch 
would  be  %-.     (12'^  rise  to  1  foot  run.) 

The  Plate  shows  how  to  lay  off  a  rafter  by  means  of  the  ordinary 
steel  square.     (See  Plate  14.) 

Pig.  A,  Plate  14,  shows  a  12-ft.  building  with  6-ft  rise  or  i/^ 
pitch. 

Fig.  .B,  Plate  14,  shows  a  4-ft.  rise,  or  I/3  pitch. 

Fig.  D,  Plate  14,  shows  the  old  method  of  laying  off  rafters.  The 
square  is  moved  along  upon  the  rafter  so  that  the  corner  comes  first 
at  d, ,  second  above     c,  third  above  d,  etc. 

The  distance  ah  is  marked  off  for  each  foot  of  run  and  the  final 
position  of  h  will  be  directly  above  one  of  the  small  letters,  c,  d  or  e. 

By  marking  down  along  the  edge  of  the  tongue  Th,  the  top  cut 
of  the  rafter  is  given.  B,y  marking  along  the  edge  of  the  square  ab 
in  its  present  position,  the  heel  cut  of  the  rafter  is  given. 


FARM  ENGINEERING. 


31 


i  C  cf  e 

Plate  14-FRA.MING  RAFTERS 


32  FARM  ENGINEERING. 

The  Author  is  a  firm  believer  in  the  use  of  the  framing .  square, 
and  consequently  does  not  dwell  upon  the  use  of  the  old-fashioned 
square. 

By  means  of  the  tables  upon  the  side  of  the  Nicholas  framing 
square,  all  rafter  cuts  may  be  laid  out  by  simply  consulting  ,the 
table.  The  results  are  accurate,  and  as  the  framing  square  costs  no 
more  than  the  old  board  rule .  square,  there  is  no  reason  why  it  should 
not  be  used  by  every  student. 

The  handling  of  carpenter  tools  cannot  be  taken  up  here,  but  a 
few  hints  on  selecting  carpenter  tools  are  not  out  of  place. 

Buy  good  tools  of  a  Standard ,  make. 

In  buying  planes,  get  those  which  have  blades  adjustable  up  and 
down  and  sidewise.    The  throat  should  also  be  adjustable. 

Saws  should .  be  fine  for  fine  work ;  12  teeth  to  the  inch  is  not  too 
fine.  For  coarse  work,  such  as  framing,  a  cross  cut  saw  should  be  as 
fine  as  8  teeth  to  the  inch.  A  rip  saw  should  have  4, or  5  teeth  to  the 
inch. 

For  finishing  work,  a  hammer  should  have  a  round  face,  while 
for  rough  work  the  square  face  is  preferred  by  many.  Don't  buy 
freak  tools  for  plain  work. 

PAINTING. 

Out-side  paint  for  barns,  fences,  etc.,  should  be  made  of  ground 
burned  clay,  and  raw  linseed  oil.  The  common  colors  are  yellow,  red 
and  brown. 

For  house  painting,  lead  oxide  (white  lead)  and  zinc  oxide  should 
be  mixed, with  raw  linseed  oil.  The  so-called  boiled  linseed  oil,  is  raw 
oil  with  some  drying  agent  added. 

The  inside  finish  should  be  bought  ready-prepared,  and  used  ac- 
cording to  directions. 

In  general,  paint  should  be  applied  in  thin  coats,  well  rubbed  in. 

The  student  must  choose  the  colors  and  types  of  finish  according 
to  his .  own  particular  taste  in  the  matter. 

PLUMBING. 

When  putting  in  closets,  sinks,  etc.,  remember  that  every  fixture 
must  have  a  trap,  to  prevent  the  back  flow  of  noxious  gases  from 
the  sewer.  The  trap  should  be  vented  directly  to  a.  ventilator  stack, 
which  must  open  through  the  roof:  The  stack  should  be  the  same 
size  as  the  sewer  pipe. 


FARM  ENGINEERING.  33 

The  traps  should  be  directly  connected  to  the  fixtures.  The  fact 
that .  a  trap  is  placed  at  the  entrance  of  the  cess  pool,  in  no  way  does 
away  with  the  necessity  of  the  fixture  traps  in  the  house. 

All  plumbers'  supply  houses  have  drawings  and  specifications 
for  the  installation  of  their  fixtures. 

Caution:  No  lead  pipe  should  be  used  in  the  water  line  from 
which  drinking  water  is  obtained.  The  water  acts  upon  the  lead 
and  a  sloiu  poison  is  likely  to  be  found  in, that  part  of  the  water  which 
has  been  standing  in  the  lead  pipe. 

It  is  nearly  always  advisable ,  to  have  plumbing  done  by  a  com- 
petent plumber,  rather  than  to  attempt  the  work  without  experience. 

ESTIMATING  QUANTITIES. 

The  student  can  become  proficient  in  estimating  quantities  of  ma- 
terial by  actual  practice  only. 

A  few  simple  rules  are  here  given  for  the  guidance  of  the  student 
in  making  estimates. 

1.  Begin  by  estimating  excavations. 

2.  Finish  foundations  and  chimneys. 

3.  Work  out  first  floor,  sides,  second  floor  and  roof  in  order. 

4.  Complete  plastering  estimate. 

t  5.     Complete  inside  finishing  estimate. 

6.  It  is  customary  to  put  all  materials  of  a  kind,  such  as  2x4 's, 
siding,  laths  ,  and  shingles  together  in  the  final  estimate.  But  it  is 
advisable  to  keep  a  copy  of  the  estimate  of  each  part  separate,  for 
the  benefit  of  the  builder. 

7.  Lumber, is  estimated  by  the  thousand  feet. 

8.  Shingles  are  estimated  by  the  thousand. 
1  bunch  =  14  of  1,000. 

(If  shingles  are  laid  4  inches  to  the  weather,  1,000  shingles  will 
cover  about  1  square. — 100  square  feet.    At  five  inches  1^  squares.) 

9.  In  estimating  flooring,  add  about  I/3  the  total  number  of  sur- 
face feet  to  the  estimate  to  make  up  for  tongues  in  3''  or  4'', flooring. 
In  case  of  6^'  "or  8''  flooring  or  ship  lap,  add  i/4  the  original  estimate. 

For  narrow  siding  I/3  must  be  added  to  the  original  estimate. 

10.  Good  paint  should  cover  ,  from  200  to  300  square  feet  of 
new  lumber  per  gallon  for  the  first  coat.  Second  coat,  300  to  400 
square  feet. 


34 


FARM  ENGINEERING. 


11.  When  the ,  necessary  number  of  nails  has  been  determined, 
consult  the  following  table.  Divide  by  number  of  nails  per  pound  to 
find  number  of  pounds  required.* 

It  takes  about  2%  pounds, of  3d  nails,  or  about  3i/^  pounds  of  4d 
nails  to  lay  1,000  shingles.      d  indicates  the  penny  of  the  nail. 


d 

length 

Number  per  lb.      [ 

in 
inches 

2d 

1 

1100  to 

1200 

Sometimes  used,  for  lathing. 

3d 

11/4 

700  to 

750 

Shingle  and  lath  nails. 

4d 

W2 

400  to 

450 

Shingle  nails. 

6d 

2 

250  to 

275 

Thin  siding. 

8d 

21/2 

125  to 

140 

For  siding,  sheathing  and  flooring. 

lOd 

3 

75  to 

90 

Sheathing  and  flooring. 

12d 

31/4 

65  to 

70 

Toe-nailing  rafters,  etc. 

16d 

31/2 

45  to 

50 

Toe-nailing  rafters,  etc. 

20d 

4 

30  to 

35 

Framing  work. 

30d 

41/2 

25  to 

30 

Framing  work. 

40d 

5 

15  to 

20 

Framing  work. 

Casing  and  finishing  nails  run  about  Yq  to  ^4  more  per  pound  than 
do  the  common  nails  listed  above. 

CHICKEN  COOPS. 

The  student  cannot  do  better  than  to  obtain  "Farmers'  Bulletin 
No.. 3"  of  the  Montana  Experiment  Station  at  Bozeman,  Montana.  As 
the  Bulletin  contains  a  reprint  of  "Farmers'  Bulletin  No.  357"  of 
the  United  States  Department  of  Agriculture,  the  knowledge  imparted 
is  very  complete,  both  in  general  poultry  culture, ,  and  in  the  details 
of  poultry  houses  construction. 

HOG  HOUSES. 

As  differences  in  latitude  and  general  weather  conditions  in- 
fluence the  type  of  hog  house  which  is  desirable  for  different  localities, 
the  student  will  necessarily  have  to  investigate  local  conditions  before 
designing  a  hog  house  or  "piggery." 

The  individual  hog  house  shown, in  Plates  15  and  16,  is  very  de- 
sirable for  brood  sows.  It  is  suitable  for  all  the  central  and  northern 
states. 

*  As  nails  are  cheaper  by  the  keg  than  by  the  pound,  it  often  pays  to  buy  a  keg 
rather   than   a   large   fraction   of  a  keg. 


FARM  ENGINEERING. 


35 


All  hog  houses  should  be  well  lighted,  provided  with  plenty  of 
fresh  air,  and  a  clean,  warm  floor. 


Plate  15— INDIVIDUAL  HOG  HOUSE 


36 


FARM  ENG INEERING. 


D  earned 
HMBainer 


Plate  16  -  INDIVIDUAL  HOG  HOUSE 

It  is  essential  that  a  sow  should  be  quiet  during  her  farrowing  period. 
The  individual  hog  house  fills  the  bill   exactly. 

It  is  built  with  a  two  by  four  frame.  The  frame  is  covered  with  drop 
siding  or  ship  lap.     The  house  is  easily  moved  from  place  to  place. 

A  small  door  about  a  foot  square  should  be  put  in  the  end  opposite  the 
large  door.  The  small  door  should  be  near  the  top.  It  provides  ventilation, 
and  allows  the  herdsman  to  drive  out  ugly  sows.  The  drawings  and  the 
picture  explain  how  the  individual  hog  house  is  built. 


COW  BARNS. 


Cow  barns,  above  all,  should  be  well  ventilated  and  lighted.  The 
most  practical  system  of  lighting  and  ventilating  consists  of  placing 
windows  rather  high  in  the  sides  of  the  barn.  The  windows  should 
be  hinged  at  the  bottom,  so  as  to  swing  inward  at  the  top.     At  the 


FARM  ENGINEERING. 


37 


sides,  there  should  be  boards  set  in  such  a  manner  that  when  the 
window  is  open,  the  in-coming  air  must  come  over  the  top  of  tlie 
windows.     Cold  drafts  are  thus  eliminated. 

The  floors  may  be  of  paving  brick  or  concrete.  In  case  of  very 
smooth,  cement  floors,  no  ice  should  be  allowed  to  collect  upon  the 
floor.  Cows  are  likely  to  slip  upon  this  film  of  ice  and  become  dis- 
abled. 


Plate  17-A  BARN  OF  EXCEPTIONAL  DESIGN 

From  the  standpoint  of  arrangement,  there  is  practically  no  improve- 
ment that  could  be  made.  The  surrounding's  are  sanitary,  and  in  summer, 
the  flower  beds  in  the  fore-ground  are  very  beautiful. 

For  the   ground  plan,    see   Plate   IS. 

The  dairy  room  should  be  some  distance  from  the  barn,  in  order 
to  exclude  all  contaminating  odors  from  the  stored  milk,  butter  or 
other  products. 

A  silo  may  be  located  near  the  cow  barn,  and  connected  to  the 
feed  way  by  a  covered  alley  way.  , 


THE  SILO. 

The  student  should  make  a  careful  study  of  the  most  up-to-date 
silos.     See  Bulletins  100  and  117,  Iowa  State  ,  College  Experiment 
Station,  Ames,  Iowa.     These  Bulletins  are  so  clear  and  concise,  that 
Lfurther  discussion  Avoiild  be  fruitless. 


^1 


38 


FARM  ENGNEERING. 


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FAEM  ENGINEERING. 


39 


Plate  19-IOWA  SILO 


Plate  20-MACHINE  SHED 


40 


FAEM  ENGINEERING. 


Two  Retjiny  Doors  S*p 


^rm 


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EL 


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FARM  ENGINEERING. 


41 


Plate  22-MACHINE  SHED 

In  spite  of  many  theories  to  the  contrary,  tlie  author  has  learned  by 
actual  field  investigations,  that  only  closed  machine  sheds  are  satisfactory. 
The  shed  in  Plates  20  and  21  is  considered,  verj;"  satisfactory. 

The  long-,  narrow  shed  in  Plate  22,  is  also  verj^  satisfactory. 

HORSE  BARN. 

The  horse  barn  should  be  separated  from  the  cow  barn  if  possible. 
The  wagon,  carriage,  and  harness  rooms  should  also  be  separated 
from  the  horse  stalls  by  tight  partitions.  The  ammonia  arising  from 
the  stalls  will  eventually  ruin  paint  and  leather. 

The  system  of  ventilating  the  horse  stable  should  be  the  same 
as  in  the  case  of  the  coav  barn.      For  size  of  stalls  see  table. 

TABLE   OF  SIZE   OF   STALLS. 

Horse  (single),  3'  S^'xlO'  or  4'xlO'  .     (From  front  of  manger.) 

*Horse   (single),  5'xlO'.     (From  front  of  manger.) 

Horse  (double),  7'xlO'  or  8"xl0^ 

Horse  (single,  box  stall)  lO'xlO',  or  10'xl2'. 

Cow  (single  stall),  3'  6"  to  4'x7^  (From  front  of  manger  to  front 
of  gutter.) 

Total  length  of  stall  from  front  of  manger  to  back  wall. 

For  horses,  14'.     16'  is  better. 

For  cattle,  11'  to  13^ 

*Horse  stalls  between  4  and  5  feet  wide  are  often  found  to  be  un- 
satisfactory, owing  to  the  fact  that  when  a  horse  lies  down  he  may 
get  his  feet  above  him  in  a  stall  wider  than  four  feet,  and  not.be  able 
to  get  them  under  him  again  in  a  stall  narrower  than  five  feet.  This 
often  requires  the  pulling  of  the  horse  out  of  the  stall  in  order  to ,  allow 
him  to  get  up. 


42 


FARM  ENGINEERING. 


Plate  23-A  NEAT  FARM  COTTAGE 


Plate  24-PARM  HOUSE 


FARM  ENGINEERING.  43 

DWELLING  HOUSES. 

As  the  location  of  the  farm,  the  climate,  the  special  weather  con- 
ditions, the  size  of  the  family,  and  the  taste  of  the  people  who  dwell 
in  farm  houses,  are  all  factors  which  govern  the  design  of  farm 
liouses,  no  plans  are  included  in  this  volume. 

The  student  should  work  out  plans  to  exactly  suit  the  conditions 
and  no  one  else  can  do  this  for  him. 

Procure  from  the  Extension  Dept.,  Bulletin  No.  1,  "Healthful 
Homes,"  Iowa  State  College,  Ames,  Iowa. 


EXAMINATION 


Note  to  Student — These  questions  are  to  be  answered  inde- 
pendently- Never  consult  the  text  after  beginning  your  exami- 
nation. Use  thin  white  paper  about  6"x9"  for  the  examination. 
Number  the  answers  the  same  as  the  questions,  but  never  repeat 
the  question.     Mail  answers  promptly  when  completed. 

QUESTIONS  FOR  EXAMINATION. 

1.  Give  two  reasons  why  farm  buildings  used  to  be  built  of  sucli 
heavy  material. 

2.  In  what  ways  does  "guess  work"  cause  buildings  to  be  unsatis- 
.    factory? 

3.  Name  three  advantages  of  the  centralized  or  single  barn  plan  for 
farm  buildings. 

4.  Tell  why  the  "distributed"  plan  of  building  is  more  satisfactory 
than  the  centralized  system. 

5.  What  factor  takes  precedence  over  all  others  in  choosing  a  buil- 
ding site  ? 

6.  What  is  meant  by  "air  drainage"? 

7.  Name. the  three  principal  classes  of  wells. 

8.  How  far  from  a  well  should  all  sources  of  contamination  be  kept? 

9.  How  should  a  well  be  lined  or  cased? 

10.  What  is  a  cess  pool  ? 

11.  What  dangers  are  likely  to  attend  the  installation  of  a  cess  pool? 

12.  Why  is  a  trap  placed  between  the  cess  pool  and  the  house  sewer 
pipe  ? 

13.  What  is  a  "septic  tank"? 

14.  Of  what  use  is  a  hospital  stall?  , 

15.  What  is  a  cremating  pit  ? 

16.  What  qualities  should  building  material  possess  to  be  sanitary?' 

17.  Give  the  three  rules  governing  the  strength  of  beams. 

18.  How  are  rafters  designed? 

19.  Why  must  rafters  have  such  a  large. factor  of  safety? 


FARM  ENGINEERING-.  45 

20.  If  a  plain  beam  12  feet  long  will  bear  a  1000-pound,  load  con- 
centrated in  the  middle,  what  evenly  distributed  load  would  it 
carry  ? 

21.  A. roof  has  a  rise  of  6''  to  a  run  of  1-foot.    "What  is  its  pitch? 

22.  What  rise,  must  a  roof  have  per  foot  of  run,  if  it  is  a  I/2  pitch 
roof? 

23.  Where  should  the  fixture  traps  be  placed  with  respect  to  plumb- 
ing fixtures  in  a  house? 

24.  Is  a  column  4"x4''  (full  size)  two  feet  long,  a  "long"  or  a 
"short"  column? 

25.  What  points .  should  be  observed  in  designing  a  hog  house  ? 

26.  Plow  much  paint  should  "first  coat"  one  side  of  a  barn  40  feet 
long,  by  20  feet  high? 

27.  Wliat. points  must  be  observed  in  designing  a  cow  barn? 

28.  Where  should  the  dairy  or  milk  room  be  placed  with  reference  to 
the  cow  barn? 

29.  What  do  we. mean  by  the  "bonding  bricks"  in  a  brick  wall? 

30.  Wliat  do  we  mean  by  the  term  "footing"  as  applied  to  walls? 

31.  A.  The  student  shall  choose  a  location  for  a  building  site,  de- 
scribe its  location  from  standpoints  of  roads,  nearness  to  fields 
and  market  and  its  sanitary  qualities. 

B.  Decide  what  type  of  farming  is  to  be  done,  whether  grain, 
hay,  dairy,  or  general  farming.  State  the  size  of  farm  and  num- 
ber of  horses,  cattle,  sheep,  hogs  and  chickens  to  be  kept  (approx- 
imate). 

C.  Decide  whether  the  centralized  or  distributed  type  of  build- 
ings are  to  be  used. 

D.  Draw  a  rough  sketch  of  farmyard  roads,  etc.,  locating  to 
scale  the  well,  cesspool,  or  closet,  and  the  buildings.  Be  SURE 
to  show  slope  of  land  by  an  arrow.  Make  the  drawing  as  a  map 
not  in  perspective. 

E.  From  here  on  the  student  may  use  all  data  available.  Make 
at  least  TWO  drawings  of  each  building;  see  that  they  are  de- 
signed CORRECTLY,  and  estimate  quantities  of  material  and 
labor  required  for  ONE  of  the  larger  buildings.  (Note.  The 
student  should  take  plenty  of  time  to  this  question.  The  author 
would  not  attempt  to  answer  question  31  in  less  than  five  days 
of  eight  hours  each.) 


46  FARM  ENGINEERING. 

WRITE  THIS  AT  THE  END  OF  YOUR  EXAMINATION. 

I  hereby  certify  that  the  above  questions  were  answered  en- 
tirely by  me. 

Signed  

Address  


THE 


Correspondence    College 

of   Agriculture 


FT.  WAYNE,  INDIANA 


FARM  ENGINEERING— Part  II 


Field  Engineering 

By  H.  BOYDEN  BONEBRIGHT.  B.  S.  A.,  A.  S.  A.  E. 

Dept.  of  Agricultural  Engineering 
Montana  Agricultural  College 


This    is  the  Second  of  a  Series  of  these  Books  giving   a   Complete   Course  of   Instruction 

in  Farm  Engineering. 


COPYRIGHT,  1912 
Iht  CORRESPONDENCE  COLLEGE  OF  AGRICULTURE 


NOTE  TO  STUDENTS 


In  order  to  derive  the  utmost  possible  benefit 
from  this  paper,  you  must  thoroughly  master  the 
text.  While  it  is  not  intended  that  you  commit  the 
exact  words  of  the  text  to  memory,  still  there  is 
nothing  contained  in  the  text  which  is  not  absolutely 
essential  for  the  intelligent  farmer  to  know.  For 
your  own  good,  never  refer  to  the  examination  ques- 
tions until  you  have  finishea  your  study  of  the  text. 
By  following  this  plan,  the  examination  paper  will 
show  what  you  have  learned  from  the  text. 

When  the  student  takes  up  the  work  of  Field 
Engineering  he  should  not  labor  under  the  impres- 
sion that  he  is  to  learn  "Civil  Engineering  at  a 
Glance."  A  Four  Year  Course  in  Civil  Engineering 
in  any  good  college  would  only  fit  the  student  for 
beginner's  work  as  a  civil  engineer. 

For  this  reason  the  author  will  endeavor  to  set 
forth  in  a  clear  practical  way  those  points  which  are 
absolutely  necessary  in  Farm  Field  Engineering. 

The  student  can  at  the  cost  of  a  few  minutes' 
time  and  the  expenditure  of  a  few  cents  for  postage 
secure  bulletins  from  various  experiment  stations 
which  will  be  very  broadening  so  far  as  results  oi 
field  engineering  work  are  concerned.  These  bullte 
tins  do  not  however  tell  how  to  go  about  the  work 
and  many  ridiculous  failures  are  attributed  to  the 
so-called  "errors"  in  these  valuable  little  books  which 
are  in  fact  due  only  to  the  lack  of  true  principles  of 
Farm  Field  Engineering. 

The  student  who  studies  these  bulletins  must 
always  ask  himself  this  question:  Do  the  conditions 
under  which  I  am  working  check  with  the  condi- 
tions under  which  the  results  set  down  in  this  bulle- 
tin were  obtained?  Do  not  jump  at  conclusions! 
Be   Sure! 


FARM  ENGINEERING 


LIST  OF  FREE  BULLETINS.   SEND  FOR  THEM. 

1.  "Land   Drainage  by   Means  of   Pumps." — Bulletin  243,  U. 

S.  Dept.  of  Agriculture. 

2.  "Duty  of  Water."— Bulletin  .56,  Agricultural  College,  N.  M. 

3.  "Measurement    of     Water     for     Irrigation." — Bulletin    53, 

Wyoming   Experiment    Station,   Laramie,   Wyoming. 

4.  "Drainage  Conditions  in   Iowa." — Bulletin  78,   Experiment 

Station,   Ames,   Iowa. 

5.  "Drainage  of  Farm  Lands." — Farmer's  Bulletin  187,  U.  S. 

Dept.  of  Agriculture. 

6.  "Land  Drainage." — Bulletin  138,  Experiment  Station,  Uni- 

versity  of  Wisconsin. 

7.  "Drainage  of  Irrigated  Lands  in  San  Joaquin  Valley,  Cali- 

fornia."— Bulletin  217,  U.  S.  Dept.  of  Agriculture. 

8.  "Drainage  of  Irrigated  Lands." — Farmer's  Bulletin  371,  U. 

S.  Dept.  of  Agriculture. 

9.  "Selection  and  Installation  of  Machinery  for  Small  Pump- 

ing Plants." — Circular  101,  U.  S.  Dept.  of  Agriculture. 

10.  "Current  Wheels." — (Their  use  in  lifting  water  for  irriga- 

tion), Bulletin  146,  U.  S.  Dept.  of  Agriculture. 

11.  "The   Use   of   Windmills   for    Irrigation    in    the    Semi-arid 

West."— Farmer's   Bulletin   304,   U.   S.   Dept.   of  Agri- 
culture. 

12.  "Practical  Information  for  Beginners  in  Irrigation." — Far- 

mer's Bulletin  263,  U.  S.  Dept.  of  Agriculture. 

13.  "The   Right   Way   to   Irrigate."— Bulletin   86,    Utah    Agri- 

cultural College  Exp.   Station,   Logan,  Utah. 

14.  "The    Construction   of   Concrete    Fence    Posts." — Farmer's 

Bulletin  403,  U.  S.  Dept.  of  Agriculture. 

15.  "Cement    Pipes    for   Small    Irrigation    Systems." — Agricul- 

tural Exp.  Station,  Tucson,  Arizona. 

16.  "Cement   Mortar   and    Concrete,"    (For    Farm    Use) — Far- 

mer's Bulletin  235,  U.  S.  Dept.  of  Agriculture. 


FARM  ENGINEERING 


17.  "Cement  and   Concrete    Fence   Posts." — Bulletin    148,   Col- 

orado  Agricultural    College    Exp.    Station,    Ft.    Collins, 
Colo. 

18.  "The  Destruction  of  Hydraulic  Cements  by  Alkali." — Mon- 

tana   Agricultural    College     Exp.     Station,     Bozeman, 
Mont.     (Bulletin  81.) 

19.  "Restoration    of    Lost    Corners    and    Subdivisions    of    Sec- 

tions."— U.  S.  Gen.  Land  Office,  Dept.  of  the  Interior, 
Washington,  D.  C. 

In  order  to  properly  understand  the  typical  surveyor's 
instruments,  drawing  instruments,  etc.,  the  student  should 
secure  the  following  catalogues.  When  he  studies  in  the  text 
about  a  level,  a  compass,  a  transit,  a  planimeter  or  other  "In- 
strument of  Precision"  he  should  turn  to  these  catalogues  and 
carefully  study  the  details   of  construction   of  the   instrument. 

The  information  will  be  of  untold  value  to  the  student  who 
expects  to  put  his  knowledge  into  practice.  By  the  careful 
study  of  the  various  makes  of  instruments  he  will  broaden 
his  understanding  of  the  work  as  well  as  of  the  instruments, 
for  the  makers  give  detailed  information  as  to  the  adjustments 
of  their  instruments  and  the  method  of  using  each  instrument. 

Gurley's  Manual,  of  American  engineers'  and  surveyors' 
instruments,  W.  &  L.  E.  Gurley,  Troy,  N.  Y.,  or  Seattle,  Wash. 

Catalogue  of  surveyors'  instruments,  C.  L.  Berger  &  .Sons, 
Boston,  Mass. 

Catalogue  of  Keufifel  &  Esser,  Keuffel  &  Esser,  New  York. 

The  Frederick  Post  Catalogue,  Frederick  Post  Co.,  Chi- 
cago, or  San  Francisco. 

Catalogue  of  Drawing  Materials,  Eugene  Dietzgen  Co., 
Chicago,  or  New  York, 

Blasting  of  Ditches,  E.  I.  Dupont  &  Co.,  Wilmington, 
Delaware. 

If  the  student  establishes  an  Engineering  Library  he  can- 
not do  better  in  the  way  of  field  engineering  books  than  to 
purchase  the  following: 


FARM  ENGINEERING 5 

Engineering    for    Land    Drainage    (Elliot),    John    Wiley    & 
Sons,  New  York. 

Mechanical  Engineers'  Pocket  Book  (Kent),  John  Wiley  & 
Sons,  New  York. 

Physics  of  Agriculture  (King),  F.  H.  King,  Madison,  Wis- 
consin. 

Theory  and  Practice  of  Surveying  (Johnson),  John  Wilev 
&  Sons,  New  York. 


FARM  ENGINEERING 


FARM  ENGINEERING 


PART  II. 


Many  attempts  at  Farm  Engineering  have  been  made  since 
the  history  of  agriculture.  The  results  of  the  best  work  have 
been  handed  down  to  us  and  by  far  the  greater  number  of 
failures  have  been  lost  sight  of.  Broadly  speaking,  the  failures 
have  all  been  due  to  ignorance,  but  this  by  no  means  indicates 
that  those  who  made  the  blunders  were  not  well  educated.  It 
is  easy  for  a  man  Avho  is  a  good  scholar  in  the  true  sense  of 
the  word  to  make  ridiculous  errors  in  drainage.  These  errors 
might  readily  be  detected  by  a  practical  ditch-digger  who  could 
neither  read  nor  write.  In  case  of  failures,  you  will  find  that 
the  educated  and  the  illiterate  invariably  jumped  at  conclu- 
sions,  with   disastrous   results. 

While  the  higher  mathematics  are  of  great  assistance  in 
doing  very  accurate  engineering  work,  there  is  no  good  rea- 
son why  by  far  the  greater  part  of  the  farm  field  engineering 
cannot  be  accomplished  by  the  man  who  has  a  thorough  knowl- 
edge of  arithmetic  and  plane  geometry.  The  following  named 
subjects  are  so  interwoven,  however,  that  he  who  hopes  to 
succeed  as  an  agricultural  engineer,  must  of  necessity  under- 
stand the  underlying  principles  upon  which  they  are  based: 

Agronomy. 
Animal  Husbandry. 
Concrete  Construction. 
Farm    Management. 
Masonry, 


FARM  ENGINEERING 


Physics. 
Sanitary  Science. 

In  the  following  discussion  the  subjects  are  taken  up  alpha- 
betically, and  not  in  order  of  most  importance. 

Agronomy. — Few  people  realize  that  the  agronomist  must 
know  (not  guess)  the  exact  needs  of  the  plants  which  are  to  be 
grown.  This  often  makes  for  success  or  failure  on  the  part  oi 
the  engineer,  as  his  work  may  be  condemned  upon  the  basis 
that  his  system  of  drainage  or  irrigation  did  not  permit  of  the 
raising  of  a  certain  crop  upon  a  given  field,  when  as  a  mattei 
of  fact,  the  crop  is  in  no  way  suited  to  the  conditions,  even 
though  the  engineering  be  done  perfectly.  The  engineer  should 
be  able  to  find  out  in  regard  to  rainfall,  temperature,  length  of 
seasons,  etc.,  so  that  he  may  not  make  ridiculous  errors  in  his 
claims  for  the  improvements  which  are  contemplated. 

The  United  States  Government  has  a  weather  bureau  in 
each  state,  and  from  these,  the  student  may  obtain  for  the 
asking,  statements  of  maximum,  minimum,  and  average  tem- 
perature for  the  months,  together  with  a  statement  of  the 
amount  of  precipitation  for  each  month.  Now,  if  the  student 
is  armed  with  such  a  statement,  and  has  a  clear  knowledge  of 
the  requirements  of  plants,  he  .is  in  a  position  to  advise  with 
some  degree  of  accuracy.  What  is  more,  he  is  able  to  foresee 
failures,  which,  if  allowed  to  occur,  might  be  attributed  to  the 
work,  rather  than  to  the  right  cause. 

The  soil  is  another  important  branch  of  Agronomy  which 
governs  very  directly  the  growth  of  plants,  the  handling  ol 
drainage  or  irrigation  water,  and  even  the  building  of  fences. 
A  system  which  may  prove  effective  upon  some  kinds  of  soil, 
may  fail  upon  another  kind.  Later  in  the  work,  the  student 
will  have  ample  opportunity  to  observe  these  points. 

Animal  Husbandry. — It  is  necessary  to  have  a  knowledge 
of  the  needs  of  the  different  farm  animals  in  order  to  make 
the  designs  of  fences  fill  all  the  needs  and  not  merely  a  part 
of  them.  The  student  who  has  observed  valuable  horses  ruined 
by  wire  cuts  will  realize  that  the  loss  of  one  horse  would  have 


FARM  ENGINEERING 


paid  well  for  the  building  of  a  properly  designed  fence  in  the 
place  of  the  barbed  wire  contraption  which  ruined  the  horse. 
But  perhaps  the  same  fence  which  ruined  the  horse  was  an 
excellent  hog,  sheep  and  cow  fence.  It  merely  needed  com- 
pletion before  it  could  be  justly  called  a  horse  fence. 

Animals  also  influence  the  physical  condition  of  the  soil 
and  its  chemical  richness  as  well.  The  drainage  of  trarftped 
stock  yards  is  a  much  harder  problem  than  the  drainage  of  an 
untramped  field.  It  often  occurs  that  the  engineer  can  accom- 
plish more  by  prescribing  a  correct  method  of  tillage,  than 
could  be  accomplished  by  any  other  means.  Study  the  habits 
of  animals,  and  what  is  required  for  them,  and  you  will  soon 
learn  that  much  of  the  field  engineering  which  you  encounter 
has  been  poorly  done. 

Concrete  Construction. — Unless  the  student  has  done  much 
work  in  concrete  construction,  he  should  be  forewarned  against 
the  "contractor"  who  claims  to  have  "unlimited  experience." 
Anyone  can  start  out  as  a  concrete  contractor  and  get  away  with 
the  money  if  one  is  so  inclined.  The  student  should  KNOW 
what  is  right  and  what  is  wrong  and  insist  on  the  work  being 
done  to  his  specifications.  He  will  be  told  many  things  by  the 
contractor,  but  he  should  remember  that  it  usually  costs  less 
to  do  poor  work  than  it  does  to  do  good  work.  This  often 
gives  much  color  to  the  statements  of  the  man  who  has  taken 
a  concrete  contract.  Know  your  subject,  specify  plainly  and 
exactly,  and  insist  upon  the  work  being  done  right. 

Farm  Management. — The  engineer  must  be  able  to  com- 
pute the  cost  of  contemplated  improvements  and  to  estimate  in 
a  fairly  accurate  way  whether  or  not  they  will  be  profitable. 
Not  all  highly  scientific  improvements  are  necessarily  profit- 
able. Striking  examples  of  unsuccessful  engineering  projects 
are  to  be  seen  in  the  irrigated  countries.  Not  that  the  dis- 
carded systems  were  unsuccessful  from  the  engineers'  stand- 
point, but  in  so  many  cases  the  water  did  not  do  sufficient  good 
when  delivered,  to  justify  even  one-half  the  original  expense. 
The  same  is  sometimes  true  of  drainage  projects,  but  the  rela- 
tive percentage  of  failures  is  comparatively  small. 


FARM  ENGINEERING 


The  laying  out  of  a  farm  in  the  first  place  is  something 
that  is  too  often  overlooked.  It  is  often  better  economy  to 
chance  present  fences,  tear  down  some  old  buildings  and  gen- 
erally rearrange  the  whole  farm  than  to  improve  upon  the  or- 
iginal plan.  It  often  happens  that  the  most  undesirable  spot 
on  the  farm  has  been  chosen  as  a  building  site  simply  because 
of  a  spring  being  near  it.  The  extra  expense  of  drilling  a  deep 
well  in  a  more  healthful  location  could  often  be  saved  in  a 
season  in  doctor  bills  alone,  to  say  nothing  of  the  other  advan- 
tages to  be  derived  from  a  really  desirable  location. 

Masonry. — The  subject  of  masonry  has  been  thoroughly 
treated  in  Part  One  of  Farm  Engineering.  An  engineer  may 
make  a  very  good  design,  and  if  this  design  be  submitted  to  a 
bungling  mason,  the  engineer  stands  a  fair  chance  to  be 
blamed  for  the  failure  which  is  almost  sure  to  follow.  Masonry, 
like  concrete  work,  is  a  field  often  invaded  by  those  who  have 
been  marked  failures  in  other  lines  of  work. 

Physics. — The  student  should  have  a  knowledge  of  ele- 
mentary physics.  The  careful  study  of  any  high  school  text- 
book will  give  the  fundamental  knowledge  necessary.  Many 
laws  of  physics  will  be  given  in  this  book,  but  they  will  not 
be  listed  as  such. 

Sanitary  Science. — As  in  the  case  of  Farm  Structural  En- 
gineering, sanitary  science  is  one  of  the  most  important  factors 
in  the  work.  The  student  should  become  thoroughly  acquainted 
with  the  laws  of  his  state  which  govern  sanitary  conditions.  It 
may  be  mentioned  here  that  in  many  cases  where  people  have, 
for  selfish  reasons,  refused  to  allow  drainage  ditches  to  pass 
through  their  lands  were  declared  a  menace  to  public  health, 
and  the  drainage  projects  were  subjected  to  no  further  hind- 
rance. A  thorough  knowledge  of  these  laws  and  rulings  will 
enable  the  enginer  to  put  through  projects  which  seem  to  be 
opposed  by  hopeless  odds.  One  should  never  give  up  until  he 
has  exhausted  all  recourses  to  laws  upon  sanitary  matters. 
Likewise,  be  sure  that  the  project  in  hand  is  not  of  such  a  na- 
ture as  to  make   it  possible  for  some   other   party  to   ruin   the 


lo FARM  ENGINEERING  

usefulness  of  the  work  by  having  it  declared  a  menace  to  the 
public  health. 

The  author  has  in  mind  the  case  of  a  small  town  which 
installed  a  sewage  system  which  emptied  into  a  small  creek. 
This  creek  had  previously  been  dammed  to  make  a  reservoir 
for  drinking  water  by  a  farmer  who  lived  a  short  distance  down 
the  stream.  No  sooner  was  the  system  ready  for  operation 
than  an  injunction  was  granted  prohibiting  the  emptying  of 
sewage  into  the  creek.  And  it  looks  at  present  as  though  the 
injunction  would  remain  active  permanently.  Even  a  slight 
knowledge  of  law  should  have  warned  an  engineer  not  to  empty 
sewage  in  a  creek  immediately  above  the  source  of  drinking 
water  of  this  farmer. 

Cases  are  on  record  in  which  large  hotels  in  the  mountain 
summer  resorts  have  been  forbidden  to  empty  sewage  into 
creeks  which  were  sources  of  water  supply  for  towns  at  least 
30  miles  down  stream.  The  student  need  have  no  trouble  upon 
this  score  if  he  will  give  careful  attention  to  the  matter  before 
beginning  a  project. 

Land  Survey. — The  science  of  surveying  is  as  old  as  his- 
tory. To  be  sure,  the  first  systems  were  crude,  but  in  their 
time  they  answered  the  purpose.  In  the  history  of  our  own 
country  we  find  that  lines  were  often  run  by  driving  to  or 
from  the  rising  sun,  and  that  the  length  of  these  same  lines 
was  often  determined  by  computing  the  circumference  of  the 
rear  wagon  wheel  and  then  counting  its  revolutions  until  the 
desired  distance  had  been  covered. 

Later  the  land  was  laid  off  by  means  of  the  surveyor's 
chain  and  the  compass.  This  method  was  far  more  nearly  ex- 
act, but  there  still  remained  much  room  for  improvement.  The 
use  of  the  steel  tape  in  measuring  lines  and  the  transit  in  de- 
termining their  directions  is  at  present  the  most  nearly  exact 
method  of  determining  distances  and  directions  which  is  open 
to  the  agricultural  engineer.  In  order  to  determine  the  length 
of  a  line  accurately,  one  must  not  only  know  how  to  use  a  sur- 
veyor's tape,  but  one  must  practice  using  it  until  he  is  able  to 


FARM  ENGINEERING 


II 


measure  a  line  1,000  feet  long  any  number  of  times  and  make 
each  answer  check  within  .05  of  one  foot.  This  is  no  easy 
task,  but  practice  will  accomplish  the  task  to  the  satisfaction  of 
all   concerned. 


Plate  I. — No.  1.     Architects  level  tilted  to  one  side  to  show  compass  box. 
No.  2.    Large  compass.    The  needle  of  this  instrument  can  be  seen. 
No.  3.     The  surveyors  transit  vvath   Vertical  circle. 
(The  plumb   bobs   of  these   instruments   have   been   drawn  up   so 
as  to  be  included  in  the  photo.) 

The  Tape. — The  tape  is  usually  100  feet  long,  although  50- 
foot  tapes  and  200-foot  tapes  are  not  uncommon.  At  each  end 
of  the  tape  one  foot  of  the  distance  is  marked  off  into  ten  equal 
divisions  or  into  tenths  of  a  foot.  In  some  cases  the  tenths  are 
subdivided  into  ten  parts,  or  into  hundredths  of  feet.  The  tape 
usually  has  detachable  wire  handles.  It  is  usually  advisable  to 
replace  the  handles  with  a  rawhide  thong  about  ^4,  of  an  inch 
wide  by  one  foot  long.  The  thong  makes  a  convenient  handle 
and  never  catches  trash  as  the  tape  is  dragged  about.     In  order 


12 FARM  ENGINEERING  

to  measure  straight,  it  is  necessary  to  know  two  points  on  the 
line  (usually  the  ends)  and  then  see  to  it  that  all  measurements 
are  made  exactly  on  that  line.  The  "rear  chainman"  (the  man 
who  attends  to  the  rear  of  the  tape)  must  signal  to  the  "head 
chainman"  to  move  left  or  right  until  he  has  the  front  end  of 
the  tape  exactly  in  line  with  the  stake  at  the  further  end  of 
the  line.  Then  the  tape  is  pulled  clear  of  all  obstructions  and 
the  rear  chainman  holds  the  zero  point  at  the  front  side  of  the 
stake  or  "pin."  The  head  chainman  then  sticks  a  pin  so  that 
its  front  side  is  just  even  with  the  one  hundred  foot  mark,  or 
such  other  mark  as  he  chooses  to  measure  to. 

The  pins  are  generally  made  of  about  No.  6  wire,  with  a 
loop  at  the  top,  and  a  pointed  bottom.  They  are  about  one 
foot  long.  In  case  the  measurements  are  made  through  grass 
or  underbrush,  a  piece  of  red  flannel  should  be  tied  in  the  loop 
of  each  stake,  as  they  are  then  much  easier  to  see.  Eleven 
stakes  or  pins  are  commonly  used.  "One  to  start  with,"  and 
then  when  ten  are  picked  up  by  the  rear  chainman  there  have 
been  ten  measurements  made,  500  feet  in  case  of  the  50-foot 
tape,  1,000  feet  in  case  of  the  100-foot  tape,  or  2,000  feet  in 
case  of  the  200-foot  tape.  In  this  way  it  is  easy  to  keep  track 
of  the  distance. 

Be  sure  to  properly  line  in  the  chainman,  or  the  measure- 
ments will  be  ridiculously  incorrect.  The  lining  in  may  be 
done  wholly  by  motions  or  by  word  (in  case  of  short  tapes). 
Never  try  to  do  field  work  accurately  without  the  use  of  a 
METAL  tape. 

"Poles"  are  usually  set  at  the  ends  of  the  line  to  aid  in 
"lining  in."  The  poles  consist  of  wood  (sometimes  gas  pipe), 
about  one  inch  in  diameter  and  six  feet  long.  They  are  painted 
red  and -white  to  assist  the  eye  in  seeing  them.  In  some  locali- 
ties blue  is  easier  to  see  than  red.  The  pole  is  set  upright  when 
th  line  has  been  determined,  and  it  proves  a  great  help  to  the 
"chainmen." 

In  meas-uring  curved  lines  it  is  often  necessary  to  use  very 
short   measurements.      There   are   other   methods    of   measuring 


FARM  ENGINEERING 13 

these  lines,  but  unless  the  operator  is  familiar  with  higher 
mathematics  it  is  better  to  use  a  tape.  When  a  line  runs  up  or 
down  hill  a  plumb-bob  should  be  used  to  determine  the  point 
at  which  the  line  should  be  held  so  that  it  is  brought  exactly 
above  the  pin.  The  tape  MUST  be  held  HORIZONTAL,  not 
parallel  to  the  earth's  surface.  Small  grades,  such  as  y^  foot 
in  one  hundred,  need  not^be  considered  in  tape  work. 

Errors. — By  the  time  the  student  has  tried  the  1,000-foot 
line  a  few  times  he  will  become  interested  in  errors.  For  this 
reason  let  us  look  into  the  matter.  If  your  tape  is  too  long 
by  )-2  inch,  then  each  measurement  will  add  to  the  error  of 
the  last  measurement.  If  the  tape  is  too  short,  then  there  will 
be  an  ever  increasing  error  in  the  other  direction.  Such  an 
error  is  a  cumulative  error.  It  is  a  very  bad  type  of  error  and 
MUST  be  avoided.  Suppose  that  you  are  using  pins  ^  inch 
in  diameter  and  the  head  chainman  places  the  pin  so  that  its 
REAR  side  is  at  the  1,000- foot  mark  instead  of  placing  the 
pin  so  that  its  front  side  is  at  the  100-foot  mark.  Then  ^ 
inch  will  be  aded  to  the  one  hundred  feet  at  every  measure- 
ment.    10  X  ^  =  2J/2  inches. 

Now  when  coming  back,  if  the  head  chainman  corrects  his 
error  and  the  rear  chainman  brings  the  zero  point  to  the  rear 
of  the  stake  each  time,  this  cuts  off  J4  inch  each  time  and  the 
line  will  be  2^^  inches  too  short.  Now  you  will  fail  to  check 
by  just  5  inches.  By  this  time  the  cumulative  error  will  be 
perfectly  apparent. 

The  compensating  error  is  not  so  bad.  Such  an  error  as 
missing  the  placing  of  a  pin  by  UlOOO  of  a  foot  is  not  so  bad 
because  in  one  case  it  may  be  in  one  direction  and  in  the  next 
case  it  will  be  in  the  other.  By  the  law  of  chance  it  is  as 
likely  to  be  one  way  as  the  other.  But  do'  not  think  that  it  is 
a  good  plan  to  depend  on  this  law.  It  often  proves  the  un- 
doing of  the  one  who  depends  on  it.  Try  to  abolish  all  errors, 
both  compensating  and  cumulative,  and  in  spite  of  your  best 
efforts  there  will  be  plenty  of  errors  and  some  to  spare. 

Remember  that  it  is  easier  to  make  a  mistake  of  100  feet 


14 FARM  ENGINEERING 

than  of  one  foot,  and  that  in  your  figures  it  is  as  easy  to  make 
a  mistake  of  1,000  as  of  1  or  .01. 

How  to  Turn  Off  a  Right  Angle  With  a  Tape.— It  often 
becomes  necessary  to  turn  a  line  at  right  angles,  in  order  to 
pass  an  object  while  measuring  a  line  or  in  order  to  find  the 
direction  of  a  "right  line"  from  a  point  in  the  line.  To  do  this 
one  should  measure  back  8  feet  on  the  line  from  the  point  at 
which  the  line  is  to  be  turned  ofif.  At  the  point,  8  £eet  back 
from  the  turning  point.,  set  a  pin  exactly  on  the  line.  Now, 
with  the  zero  point  held  at  the  turning  point  or  stake,  scratch 
the  arc  at  the  6-foot  point  at  what  you  believe  to  be  right 
angles  to  the  main  line.  Make  the  arc  cover  several  degrees, 
in  order  to  avoid  any  delays.  Now,  with  the  zero  point  held 
at  the  point  8  feet  back  on  the  main  line  find  the  point  in  the 
scratched  arc  where  the  10-foot  mark  crosses  the  scratch.  The 
point  is  in  a  line  which  is  at  right  angles  to  the  main  line  at 
the  original  turning  point.  The  foregoing  is  based  upon  the 
fact_that  the  square  of  the  base  plus  the  square  of  the  side  of 
a  right  angle  triangle  is  equal  to  the  square  of  the  hypothenuse. 
8X8  =  64;6X6  =  36; 
10  X  10  =  100;  64  +  36=  100. 

In  case  of  long  lines,  one  may  use  60  feet,  80  feet  and  100 
feet.  This  gives  greater  accuracy.  In  case  the  transit  is  handy 
it  is  usually  advisable  to  turn  off  the  angles  with  it.  It  is 
quicker.  B)^  bisecting  the  right  angle  one  is  able  to  turn  off 
the  45  degree  angle  with  little  trouble. 


INSTRUMENTS   BY   WHICH   DIRECTIONS   ARE 
DETERMINED. 

The  Compass. —  (See  Plate  1,  Fig.  2.) — In  the  preliminary 
surveys  of  land  the  compass  is  often  used  to  determine  the 
direction  in  which  lines  should  be  run.  The  fact  that  the  same 
end  of  a  magnetized  needle  always  points  approximately  north 
enables  the  instrument  makers  to  design  an  instrument  which 
can  be  used  to  determine  the  direction  of  lines.     The  magnetic 


FARM  ENGINEERING ij 

needle  is  balanced  upon  a  pivot  in  the  middle  of  a  glass  covered 
cavity.  Around  this  cavity  are  the  degree  marks,  by  w^hich  one 
is  able  to  read  the  number  of  degrees  the  line  varies  from  the 
approximate  north  and  south  line.  The  engineer  who  wishes 
to  do  good  work  with  a  compass  must  exercise  great  care  for 
the  following  reasons : 

1.  The  "North  magnetic  pole"  lies  east  of  due"  north,  and 
consequently  at  different  points  on  the  earth's  surface  the 
"declination"  or  "variation"  from  the  true  north  and  south  line 
is  different  in  extent.  And  what  is  more,  the  North  magnetic 
pole  does  not  remain  in  exactly  the  same  place  all  the  time. 
All  god  instrument  makers  give  directions  in  their  catalogues 
for  the  finding  of  the  declination  of  the  needle  for  different 
points  in  the  U.  S.  at  dift'erent  times.  By  the  use  of  these 
tables  one  is  able  to  determine  fairly  accurately  the  direction 
of  a  line.     (See  Gurley's  Manual.) 

2.  Local  attractions  often  interfere  with  the  needle  of  the 
compass,  as  for  example,  a  bar  of  iron  held  near  the  instrument 
will  draw  the  needle  away  from  the  true  line.  The  presence  of 
large  bodies  of  iron  ore  are  likely  to  draw  the  needle  out  of  line 
and  make  the  readings  entirely  wrong. 

From  the  foregoing  it  will  be  seen  that  the  compass,  while 
an  excellent  instrument  for  rough  work,  is  likely  to  prove  of 
little  value  to  the  agricultural  engineer  who  must  do  accurate 
work.  For  these  reasons  but  little  emphasis  is  laid  upon  the 
instrument  here.  The  makers  of  good  compasses  furnish  cata- 
logues telling  how  to  adjust  the  individual  instruments  and  how 
to  determine  the  North  and  South  line,  or  the  declination  of 
the  needle.     (See  Plate  1,  Fig.  3.) 

The  Transit. — Transits  are  provided  with  a  compass  needle 
and  graduated  circle  so  that  they  may  be  used  as  a  compass  in 
case  one  so  wishes.  But  they  are  also  provided  with  circles 
so  graduated  that  angles  may  be  accurately  measured  with 
them.      (See   Plate    1,    Fig.    1.) 

The  Architect's  Level.— The  architect's  level  is  often  pro- 
vided  with   a  magnetic   needle   and   graduated   circle   by   which 


i6 FARM  ENGINEERING 

one  may  determine  the  direction  of  the  given  line.  The  same 
general  rules  which  govern  the  errors  in  compass  observations 
hold  true  when  applied  to  the  magnetic  needle  readings  of  the 
transit  or  the  architect's  level. 

The  Plumb  Line. — By  means  of  a  weight  called  a  "'plumb- 
bob,"  attached  to  a  "plumb-line,"  lines  can  be  determined 
which  are  vertical  to  the  earth's  surface.  As  the  center  of 
gravity  of  the  earth  is  presumed  to  be  its  center,  then  all  plumb 
lines  will  naturally  hang  with  the  lower  ends  pointing  toward 
the  center  of  the  earth.  For  this  reason  no  two  plumb  lines 
can  be  exactly  parallel.  For  by  geometry  we  learn  that  two 
parallel  lines  will  never  meet,  no  matter  how  far  they  are  ex- 
tended. Now,  as  all  plumb  lines  meet  at  the  center  of  the 
earth,  it  stands  to  reason  that  they  are  not  parallel.  The  best 
plumb-bobs  are  made  of  steel  or  brass,  hollowed  out  on  the 
inside.  The  cavity  is  filled  with  mercury.  This  is  done  to 
give  the  greatest  possible  weight  for  the  size.  (The  wind  does 
not  bother  such  a  bob  nearly  so  much  as  a  lighter  one.) 

The  plumb-bob  is  an  instrument  which  the  surveyor  must 
constantly  use.  It  is  simple,  and  under  most  conditions  it  is 
very  accurate.  It  is  sometimes  influenced  by  the  presence  of 
great  bodies  of  earth  at  O'^e  side  of  it.  but  for  all  practical  pur- 
poses one  need  not  hesitate  to  use  the  plumb-bob  with  absolute 
confidence. 

Bubbles  and  Bubble  Tubes. — The  direction  of  lines  is  also 
determined  by  means  of  glass  tubes  nearly  filled  with  ether. 
The  tubes  are  not  straight  on  the  inside,  but  they  are  slightly 
bent.  Thus,  when  the  tube  lies  on  the  side  the  ether  seeks  the 
lowest  level  and  the  bubble  of  ether  gas  is  forced  to  the  highest 
point  in  the  tube.  As  one  end  of  the  tube  is  raised  the  ethef 
flows  to  the  other  end  and  the  bubble  seeks  the  higher  end. 
In  cheap  levels  the  glass  tubes  are  not  accurately  made  and 
consequently  are  not  sensitive  to  slight  movements  of  the  tube, 
but  in  the  high-grade  instruments  the  tubes  are  so  ground  that 
the  slightest  alteration  in  the  position  of  the  tube  is  instantly 
shown  by  the  position  of  the  bubble.     The   two  principal  uses 


FARM  ENGINEERING 


17 


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o  -^ 


FARM  ENGINEERING 


of  the  bubble  tubes  are  to  determine  (a)  plumb  lines;  (b)  hor- 
izontal lines. 

General  Principles  Governing  the  Adjustment  of  Bubble 
Tubes. — It  stands  to  reason  that  a  glass  tube  so  delicately 
ground  as  a  bubble  tube  must  be  accurately  set  in  an  instru- 
ment in  order  to  secure  accuracy.  Nearly  all  tubes  are  sur- 
rounded by  a  brass  tube  which  is  held  by  adjusting  screws. 
The  system  used  in  setting  the  bubble  tube  consists  of  bring- 
ing the  tube  into  such  a  position  that  the  center  of  the  bubble 
is  directly  under  the  center  of  the  bubble  tube.  The,n  the  posi- 
tion of  the  tube  is  reversed  and  if  the  instrument  is  in  perfect 
adjustment  the  center  of  the  bubble  again  comes  under  the 
center  mark  of  the  tube. 

Examples. — To  Adjust  a  Carpenter's  Level. — First,  lay  the 
level  on  a  solid  base  and  block  up  the  lower  end  until  the 
bubble  comes  -to  center.  Now  carefully  change  ends  with  the 
level.  If  the  bubble  again  comes  to  center  the  level  is  correctly 
adjusted.  If  it  does  not,  then  adjust  for  one-half  the  differ- 
ence and  repeat  the  trial  until  the  correct  adjustment  is  arrived 
at.  To  Adjust  the  Plumb  Bubble. — Draw  a  line  on  a  vertical 
wall  along  the  side  of  the  level  when  the  plumb  bubble  is  in 
center  of  the  tube.  Now  turn  the  level  on  the  other  side  of 
the  line  with  the  same  edge  (the  bottom  of  level)  to  the  line. 
If  the  bubble  centers  then  the  plumb  tube  is  in  correct  adjust- 
ment.    If  not,  adjust  for  one-half  the  difference  as  before. 

In  the  first  place  we  make  the  axis  of  the  bubble  tube  par- 
allel to  the  bottom  of  the  level.  In  the  second  place  we  make 
the  axis  of  the  bubble  tube  at  exactly  right  angles  to  the  bot- 
tom of  the  level.  Thus  we  can  determine  a  horizontal  or 
"level  line"  and  a  vertical  or  plumb  line  by  the  same  instru- 
ment  (the  carpenter's  level). 

In  the  case  of  the  small  bubble  tubes  on  the  compass  and 
transit  bases,  the  object  is  to  make  it  possible  to  adjust  the 
base  of  the  instruments  so  that  they  will  be  level.  In  the  case 
of  those  tubes  beneath  the  telescopes,  the  object  is  to  make  the 
"line  of  sight"  level,  or  parallel  to  the  axis  of  the  bubble  tube. 


FARM  ENGINEERING 19 

Thus,  in  the  eye  level  the  axis  of  the  bubble  tube  may  be  par- 
allel to  the  line  of  sight  and  accurate  work  may  be  done,  even 
th9ugh  the  wyes  are  out  of  adjustment.  But  in  case  the  wyes 
are  out  of  adjustment  the  instrument  must  be  leveled  up  each 
time  the  tube  is  revolved  upon  the  vertical  axis. 

*A11  makers  of  good  instruments  furnish  directions  for  ad- 
justing their  mstruments,  and  these  directions  should  be  fol- 
lowed carefully.  All  instruments  which  are  so  made  that  their 
accuracy  depends  upon  bubble  tubes  should  be  handled  with 
great  care  and  frequent  trials  should  be  made  in  order  to  be 
absolutely  sure  that  none  of  the  adjutsments  are  "off."  For  it 
must  be  remembered  that  the  engineer's  reputation  often  de- 
pends upon  the  accuracy  of  his  instruments.  It  is  much  easier 
and  by  far  more  satisfactory  not  to  make  errors  than  it  is  to 
try  to  explain  how  the  errors  were  made. 


PHOTOGRAPHY. 

While  it  is  not  absolutely  necessary  for  an  Agricultura^l 
Engineer  to  be  able  to  take  photographs,  yet  in  no  other  way 
can  he  so  plainly  describe  and  show  his  work  as  by  a  photo. 
The  United  States  Government  requires  photos  of  the  differ- 
ent federal  enterprises,  as  they  progress.  This  not  only  gives 
a  clear  and  definite  idea  of  the  rate  of  progress,  but  it  serves 
as  a  record  of  the  work  after  it  is  done.  If  the  Engineer  is 
able  to  photograph  his  work  it  helps  him  in  many  ways.  It 
shows  up  the  work  to  the  best  advantage.  It  saves  a  great 
deal  of  time  and  labor  which  would  be  required  in  making 
drawings  to  show  progress.  And  in  case  of  legal  proceedings 
the  photo  is  absolute  evidence.  The  photos  are  also  useful  in 
showing  prospective  clients  the  work  which  you  have  ac- 
complished. 

For  the  above  reasons  it  is  well  to  have  a  camera  and  to 
be  able  to  take  photos  with  it.     (See  Plate  3,  Fig,  6.) 


*See  Gurley's  Manual.     It  is  a  good  text  book  of  American 
Surveyors'  Instruments.     Also  Burger's  Catalogue. 


J 


Plate  III. — No.  1.     Avtiiiteefs  level.     This  level  is  of  the  Wye  type  with 
Compass   box  and  circle  graduated  in   degrees. 

No.  2  is  a   regular  type  of  Dumpy  level.     Notice  the  absence  of 


Wye?. 

No.  3. 

No.  4, 

No.  5. 

No.  6. 


A  transit  with  vertical  circle. 

A  Philadelphia  rod  with  target. 

Two  steel   flag  staffs,  or  "range  poles." 

A  5  in.  by  7  in.  camera  valued  at  $180.00  with  which  most 
of  the  pictures  in  this  book  were  taken.  (A  cheaper  camera  could 
have  been  made  to  do  better  work  where  water  is  shown.) 


FARM  ENGINEERING 21 

The  Camera. — -From  the  standpoint  of  the  Engineer,  the 
most  expensive  is  not  always  the  most  desirable  camera.  The 
most  of  the  pictures  in  this  book  were  taken  with  a  $180.00 
camera.  Yet  in  those  pictures  which  show  movement  there  is 
a  blur  which  would  not  have  been  shown  by  a  camera  of  the 
Rapid  Rectilinear  type,  which  could  have  been  bought  for 
$15.00.  A  simple,  easily  adjusted  camera  with  a  lens  which  can 
be  depended  upon  to  take  instantaneous  exposures  in  bright 
light  is  the  most  suitable  for  the  Engineer.  The  author  has 
had  in  his  charge  cameras  ranging  in  price  from  $5.00  to 
$200.00,  and  for  field  work  there  is  no  doubt  that  the  simple 
camera  with  a  simple  lens  and  shutter  is  more  suitable  for  the 
Agricultural  Engineer.  An  Engineer  cannot  take  the  time  nec- 
essary to  do  "artistic  photography"  as  the  term  is  understood 
by  the  photographer.  What  is  needed  is  clear  pictures  bringing 
out  plenty  of  contrast  and  detail,  regardless  of  the  artistic 
blending  of  light  and  shade,  so  necessary  to  portrait  work. 

Every  company  furnishes  directions  for  the  manipulation 
of  the  cameras.  A  few  simple  solutions,  two  or  three  granite 
iron  pans,  a  printing  frame  and  a  dark  closet  provided  with  a 
simple  "ruby"  light  will  often  take  the  place  of  a  wheelbarrow 
load  of  patent  developers,  fancy  automatic  devices  and  expen- 
sive apparatus  which  some  people  think  they  must  have  in  or- 
der to  "do  photographing. 

The  detail  of  the  work  cannot  be  taken  up  here,  however. 
The  student  will  find  that  photography,  as  the  Engineer  needs 
it,  is  simple,  and  he  will  find  that  every  day  new  cases  arise 
which  enable  him  to  save  time  and  add  to  the  efficiency  of  his 
work  by  the  use  of  a  camera. 


LAND  SURVEYING. 

Land  surveying  is  done  for  one  of  two  general  purposes. 
In  the  first  place,  the  surveying  was  done  to  establish  the 
boundary  lines  of  townships,  sections,  etc.  The  boundaries 
were  supposed  to  be  marked  permanently  by  so-called  "monu- 


22 


FARM  ENGINEERING 


merits,"  constructed  of  stones,  pegs,  stumps,  trees,  holes  in  the 
ground  or  holes  filled  with  charcoal.  The  stone  and  the  char- 
coal monuments  lasted  pretty  well  but  the  holes  in  the  ground 
filled  up,  the  pegs,  stumps  and  trees  rotted  away,  and  the  sec- 
ond use  of  land  surveying  becomes  apparent. 

It  is  to  locate  the  old  corners,  re-establish  them  or  if  need 
be,  locate  new  ones.  In  order  to  do  this  work  correctly  one 
must  do  it  according  to  United  States  regulations.  These  rules 
are  very  clearly  given  in  the  little  circular  entitled  "The  Re- 
storation of  Lost  or  Obliterated  Corners  and  Sub-divisions  of 
Sections."  Write  to  the  United  States  Land  OfHce,  Department 
of  the  Interior,  Washington,   D.   C,  for  this  circular.     Follow 


^ 


t<- B'- 


Plate  4.  In  running  the  line  AB,  the  engineer  found  it  necessary  to  turn  a 
right  angle  at  B.  He  measured  back  8  ft.  to  C.  and  struck  the  arc 
FD,  10  ft.  from  C.  Then  he  struck  the'  arc  HE,  6  ft.  from  B.  By 
drawing  the  line  from  B  through  the  intersection  of  arcs  FD  and  HE, 
he  obtained  the  line  BX,  which  is  at  exactly  90  degrees  to  AB. 

its  directions  and  do  not  try  to  do  the  work  according  to  any 
other  method.  Where  a  question  of  law  is  concerned,  do  not 
permit  theoretical  considerations  to  interfere  with  the  rules 
which  are  so  plainly  laid  down. 


FARM  ENGINEERING 


23 


It  is  often  necessary  to  determine  the  area  of  irregular 
fields.  For  the  surveyor  who  has  not  had  higher  mathematics 
this  work  requires  more  field  work  than  for  the  surveyor  who 
has  a  thorough  knowledge  of  higher  mathematics.  However, 
the  work  can  be  done,  by  dividing  the  fields  into  right  angled 
triangles,  and  applying  the  formula.  The  area  of  a  right  angle 
triangle  is  equal  to  Vz  the  product  of  the  perpendicular  and 
base. 

With  a  compass,  a  transit,  or  an  architect's  level  set  up  at 
a  point  on  a  boundary  line  which  in  your  judgment  will  be  the 
point  at  which  a  perpendicular  from  a  certain  corner  will  meet 
your  boundary  line.  Turn  off  90  degrees  and  by  repeated 
trials  locate  the  desired  point.  Now  with  a  tape  measure  the 
base  and  the  perpendicular  lines  of  the  triangle.  Multiply  one 
by  the  other  and  divide  by  two  to  get  the  area  of  the  triangu- 
lar part  of  the  field.  Continue  until  the  field  has  been  divided 
into  right  triangles  and  all  of  these  have  been  measured.  Now 
add  the  areas  of  all  and  the  sum  will  be  the  area  of  the  irregu- 
lar field. 


Plate  5.  Fig.  1.  In  figure  1  the  field  AFBE  is  first  divided  by  line  A  D, 
tlien  each  of  the  fields  is  divided  into  two  right  angle  triangles.  The 
area  is  equal  to  the  sum  of  the  four  triangular  fields. 

Fig.  2.  In  figure  2  a  field  of  irregular  shape  is  bounded  on  one 
side  by  a  crooked  line  (Pine  Creek).  After  the  right  triangles  Uce 
and  Zda  have  been  laid  off,  the  line  X  Y  is  laid  off  at  right  angles 
to  c  e  and  d  B.  Then  the  short  lines  N  N  N  N  etc.,  are  measured  and 
the  small  pieces  of  land  calculated.  The  sum  of  all  the  subdivisions 
will  equal  the  area  of  the  field. 


24 FARM  ENGINEERING  

Example:  (See  Plate  5,  Fig.  1.)  In  this  example  it  hap- 
pens to  be  easier  to  establish  a  new  line  A  B  upon  which  to 
set  up  the  instrument. 

The  line  A  B  is  first  established.  Then  the  point  C  is  lo- 
cated by  trials.    The  area  of  A  C  F  is  equal  to  (AC  ^  FC)  -^  2. 

Now  locate  D  by  trials  so  that  E  D  is  at  right  angles  to 
AB,  then  the  area  of  ADE  will  equal  (AD  X  DE)  ^  2,  and  the 
area  of  DEB  will  be  equal  to  (DB  X  DE)  -  2.  Now  all  the 
different  parts  of  the  field  have  been  measured  and  all  that  re- 
mains is  to  add  the  areas  of  the  four  triangles  and  the  result 
will  be  the  exact  area  of  the  field. 

When  the  lines  of  a  field  are  curved,  as  by  a  creek  bank, 
it  often  becomes  necessary  to  use  ingenuity  in  determining  the 
area.  It  is  usual  to  lay  off  as  much  of  the  land  as  possible  in 
fields  having  straight  lines  and  then  determine  the  area  of  the 
remainder,  as  in  example  given  below.  (See  Plate  5,  Fig.  2.) 
The  area  of  C  F  B  is  equal  to  (FC  X  CB)  -^  2. 
Determine  area  of  U  X  Y  Z,  as  in  case  of  field  having  straight 
lines  for  boundaries.  You  will  have  to  lay  out  X  Y.  Now  at 
frequent  intervals  measure  the  distances  n,  n,  nn,  nn,  etc.,  and 
compute  the  small  areas  as  accurately  as  possible.  Add  them 
all  to  the  area  of  XYZU  and  the  area  of  the  field  is  obtained. 

Caution. — Always  use  the  same  units  of  measure  on  the 
field  and  when  the  results  are  obtained  in  the  same  units  one 
may  then  change  these  units  to  any  other  units  as  desired. 
Do  not  measure  one  triangle  in  feet  and  inches,  another  in  feet 
and  tenths  and  still  another  in  rods,  feet  and  inches.  Stick  to 
one  unit  of  measure. 

To  Determine  the  Area  of  An  Irregular  Field  by  Means 
of  the  Polar  Planimeter. — If  the  student  has  an  accurate  draw- 
ing putfit,  including  a  good  and  accurate  protractor,  the  work 
of  calculating  the  area  of 'an  irregular  field  is  not  so  difficult. 

Measure  the  sides  of  the  field  accurately  and  the  angles 
exactly.  Now  draw  a  map  of  the  field  to  some  scale,  taking 
great  care  to  make  each  angle  and  line  exactly  at  the  right 


FARM  ENGINEERING 


25 


26  FARM  ENGINEERING 


angle  and  of  exactly  the  right  length.  By  means  of  the  Polar 
Planimeter  the  exact  area  of  the  field  as  mapped  may  be  de- 
termined in  square  inches.  Now  suppose  thfit  we  let  each  rod 
of  the  field  (a  small  field)  'be  represented  by  one  inch.  After 
measuring  the  map  we  find  that  it  has  exactly  92.65  square 
inches  of  area  included  inside  the  boundary  lines.  Then  by 
dividing  the  total  number  of  square  inches  of  area  by  160  (the 
number  of  square  rods  in  an  acre)  we  get  .5790  of  an  acre. 

This  is  all  right  for  a  small  field,  but  suppose  the.  field  to 
be  larger.  Then  we  may  let  one-tenth  inch  equal  a  rod  and 
then  each  square  inch  will  equal  100  square  rods.  So  after  the 
number  of  square  inches  in  the  map  has  been  determined  we 
multiply  by  100  and  divide  by  160  to  get  the  number  of  acres. 
Any  scale  may  be  used,  but  when  a  very  small  map  is  made 
for  a  very  large  field  the  error  is  likely  to  amount  to  too  great 
an  area. 

The  planimeter  should  be  used  with  great  care  and  the 
area  of  the  map  should  be  measured  not  less  than  three  times. 
If  the  answer  varies  more  than  one  one-hundredth  of  an  inch 
the  work  should  be  repeated  until  the  answer  checks  within 
one  one-hundredth  of  a  square  inch. 

The  different  styles  of  planimeters  vary  so  much  that  no 
exact  rules  can  be  given  here,  which  will  govern  the  use  of 
the  individual  instrument,  but  a  few  general  rules  are  not  amiss. 

1.  Never  try  to  run  a  planimeter  when  excited  or  ner- 
vous, as  the  shaking  of  the  hand  will  spoil  the  accuracy  of 
the  work. 

2.  Always  draw  the  map  on  a  good,  strong  paper  and  do 
not  let  it  become  wet  after  the  map  is  made.  The  swelling  and 
the  distortion  of  the  paper  will  spoil  the  accuracy  of  the  result. 

3.  Never  draw  the  map  with  a  blunt  pencil.  Always  use 
a  sharp  pencil  of  hard  lead.  The  error  of  the  width  of  a  thick 
line  is  often  great. 

4.  Be  careful  to  get  all  lines  the  right  length. 

5.  Be  sure  to  lay  all  angles  off  exactly  right.  In  general, 
be  accurate. 


FARM  ENGINEERING 


27 


To  Run  a  Division  Line  Through  an  Irregular  Field  Cutting 
Off  a  Certain  Number  of  Acres. — The  Line  to  Be  Parallel 
to  Another  Straight  Line. 


Xo 


^'77- 


->^ 


Plate  7.  Example.  -Eiin  a  line  through  tlie. field  in  Cut  7  so  as  to  leavp 
seven  a^-res  next  Bear  Creek.  Tlie  line  to  run  parallel  to  the  line 
A  B.  First  we  find  that  the  side  A  B  is  40  rods  long.  The  angles 
are  right  angles  (90  degrees).  Th^  field  contains  exactly  12  acres. 
We  now  subtract  7  from  12  leaving  .5.  Then  as  field  N  must  contain 
seven  acres  we  know  that  field  V  will  contain  five  acre-:.  Dividing  the 
total  number  of  square  rod?^  in  five  acres  by  forty  (the  length  of 
A  B)  we  get  twenty  rods  as  the  width  of  the  field  P.  160X5=800 
square  rods  in  five  acres.  800-4-40=20.  We  now  measure  off  twenty 
rods  along  each  side  and  establish  line  v/hich  divide-  the  field  at 
exactly  the  desired -point,  and  at  the  same  time  it  is  parallel  to  the 
line  A  B. 

It  often  happens  that  a  field  has  but  one  irregular  side.  If 
the  corners  are  exactly  90  degrees  and  the  three  sides  straight, 
then  all  that  is  necessary  is  to  subtract  the  required  number  of 
acres  from  the  total  number  of  acres.  Measure  off  the  neces- 
sary distance  along  the  side  lines  and  establish  the  line. 

But  suppose  the  line  must  join  the  irregular  side  of  the 
field.  The  question  becomes  harder.  Now  by  higher  mathe- 
matics one  could  calculate  the  location  of  the  line.  But  with 
the    planimeter    the    Agricultural    Engineer    can    locate    it    in    a 


28 FARM  ENGINEERING         

short  time.  First,  calculate  the  area  into  the  units  of  the  map, 
(square  inches).  Now  draw  in  a  light  line  parallel  to  the  de- 
sired line  at  the  place  where  you  estimate  the  line  should  be 
drawn.  Try  with  the  planimeter.  Keep  trying  new  lines  until 
the  desired  area  is  cut  off.  Be  sure  that  the  line  is  parallel  to 
the  desired  line.  Now  measure  off  the  distance  which  this  line 
is  from  the  line  to  which  it  is  parallel,  change  to  rods  and  pro- 
ced  to  measure  off  the  distances  in  the  field. 


c 

Plate  8.  Example.  Run  a  line  parallel  to  C  D  to  cut  off  four  acres  from 
the  field  next  Squaw  River.  The  field  has  no  angle  of  90  degrees. 
The  field  is  first  found  to  contain  9  acres.  This  is  found  by  making 
the  map,  but  it  is  not  absolutely  necessary  information.  It  does  how- 
ever guard  the  engineer  from  trying  to  cut  off  more  than  the  field 
contains.  The  map  is  drawn  to  scale  and  a  trial  line  L  M  is  drawn 
(lightly).  Field  J  is  measured  with  the  Polar  Planimeter.  It  is  too 
large.  Second  trial  line  P  T  proves  nearly  correct.  Line  X  Y  proves 
to  be  right.  The  distance  C  Y  is  measured  on  the  map  and  the  units 
changed  to  rods.  A  right  line  from  some  point  on  D  C  near  the 
river  end  of  the  line  is  now  measured  and  its  length  changed  to  rods. 
Now  go  to  the  field  and  lay  off  the  distance  C  Y  and  R  S  and  establish 
line  X  Y  in  the  field.  Field  J  contains  the  correct  area  and  X  Y  is 
parallel  to  C  D. 

By  the  use  of  an  accurate  map  and  the  planimeter  the 
Engineer  can  perform  all  of  the  divisions  of  irregular  fields 
which  may  come  up.     But  in  all  this  work  he  must  be  accurate. 

Caution. — It  is  not   safe  to  take   a   farmer's  word  for  the 


FARM  ENGINEERING 29 

size  of  an  irregular  field.  The  engineer  is  likely  to  find  that  a 
field  has  a  much  greater  or  less  area  than  the  farmer  tells  him 
the  field  contains.  One  is  likely  to  find  himself  trying  to  cut 
ten  acres  off  a  seven  acre  field  if  one  does  not  first  determine 
the  area  of  the  field. 


MAPS  AND  DRAWINGS. 

Instruments. — While  it  is  very  desirable  to  have  a  large 
and  expensive  mechanical  drawing  set,  it  is  by  no  means  neces- 
sary to  good  work. 

A  board,  12"  x  14",  with  one  end  planed  until  it  is  straight 
and  smooth  is  all  that  is  necessary  for  ordinary  work. 

(For  planimeter  work,  a  large  board  30"  x  36"  should  be 
used.) 

A  "T"  square  for  horizontal  lines. 
A  45  degree  triangle.     (About  6" .) 
A  30-60  degree  triangle.     (About  5".) 
A  right  line  pen.  l 

A  set  of  combination  dividers,  which  carry  either  points, 
pencil  or  pen,  for  circular  drawing. 

A  triangular  scale  with  the  inches  divided  into  tenths, 
twentieths,  thirtieths,  etc.,  is  necessary  for  this  work. 

A  protractor  with  which  to  lay  off  angles  is  also  very 
desirable. 

Plain  drawings  should  be  made  on  heavy  paper.  These 
drawings  should  be  made  in  pencil  first,  then  inked  in  with 
black  waterproof  ink. 

The  title  of  the  drawing  should  describe  the  land  which  it 
portrays,  and  the  scale,  1  inch  equals  1  rod,  or  1  inch  equals 
10  rods,  etc.,  should  be  placed  in  plain  sight. 

An  arrow  pointing  north  should  also  be  placed  in  some 
conspicuous  place  on  the  drawing. 


30 FARM  ENGINEERING 

In  case  of  creeks,  arrows  should  be  placed  either  in  the 
creek  or  along'  the  bank  to  show  direction  of  flow.  In  case  of 
tile  drains  or  irrigation  ditches,  this  is   also  necessary. 

In  the  drawing  of  maps  remember  to  use  the  sign  (')  to 
represent  feet  and  the  sign  (")  to  represent  tenths  of  feet,  not 
inches.  It  is  well  to  write  out  the  dimensions  in  fnil  if  the 
drawing  is  of  great  importance.  Thus  9  feet  or  17. S  feet.  Tliis 
excludes  all  possibility,  of  error.  I'\lany  do  not  I'ise  th.2  sign 
(")  at  all.  Thus  the}^  write  17. S',  which  , is  all  very  v/eil  unless 
the  point  happens  to  be  rubbed  out. 

/  In    general,    make   the    drawings    accurate    rather    tlian    ar- 

vJtistic,  plain   rather  than   flowery,   simple  rather  than  technical. 

Fences.— After  the  boundaries  of  a  held  have  been  decided 
upon  it  becomes  necessary  to  fence  it.  Tiie  ff?r.r->io-  of  fields 
has   been   practiced   to    some   erTtent    since    -'"e        -  of   agri- 

culture began.  In  the  first  pi  ace  the  methods  were  crude. 
Lines  of  stones  were  laid  upon  the  ground  and  n-:~'--°  f.-^-ones 
were  piled  on  top  of  them  until   a  kind  of  barrier  rmed. 

Tree  trunks  and  brush  v/ere  also  vs^d  as  fences.  These  methods 
of  fencing,  though  crude,  are  used  in  some  p^arts  of  the  United 
States  todav.  Ljfter  boards  were  broug-ht  in_to  1^=?  as  fencing 
material.  They  are  used  today  in  many  parts  of  the  country, 
especially  where  tight  board  fences  are  buijt.  These  serve  as 
wind-breaks,  as  well  as  fences.  Pole  fences  have  also  been 
used  a  g'reat  deal  in  the  United  States  for  confining  live  stock 
and  for  protection  from  the  attacks  of  hostile  Indians. 

By  far  the  greater  part  of  the  modern  fencing  in  this  coun- 
try is  now  done  with  wire.  The  wfire  ma}^  be  smooth  or 
barbed.  It  may  be  strung  upon  poles  in  single  strands  or  it 
may  be  woA^'en  into  the  form  of  wire  netting.  The  latter  is 
much  the  better  for  use  in  the  fencing  in  of  horses  and  well- 
bred,  valuable  cattle.  It  is  also  to  be  preferred  as  a  hog  or 
sheep  fence,  because  it  renders  it  next  to  impossible  for  the 
animals  to  escape. 

It  is  to  be  preferred  to  singde  strand  fence  because  it  is 
more  effective  as  a  barrier  and  at  the   same  time   it  turns  the 


FARM  ENGINEERING 31 

stock  without  injuring-  the  animals  in  the  slightest.  Many  a 
farmer  could  well  afford  to  take  down'  his  barbed  wire  fence 
and  replace  it  with  the  best  grade  of  wire  net  fence!  The  loss 
caused  by  the  old  barbed  wire  fences  has  in  manv  cases  run 
into  the  hundreds  of  dollars  in  a  single  night.  (Nig:ht  thunder 
storms  often  frighten  horses  into  the  wire  fence  which  cannot 
be  seen  in  the  darkness.) 

For  the  fencing  of  hogs  and  cattle  a  wire  net  fence  of 
about  36"  to  40"  surmounted  by  two  or  three  well  stretched 
barbed  wires  makes  an  excellent  barrier,  both  from  the  effi- 
ciency and  the  humane  standpoints.  For  horses  it  is  well  to 
use  a. netting  fence  not  less  than  48"  inches  high  with  one  or 
two  No.  8  smooth  wires  tightly  .stretched  above  the  netting. 

The  question  of  wire  has  already  been  settled  very  satis- 
factorily. We  can  buy  fence  that  v/ill  hold  out  mosquitos, 
stronger  fence  that  will  resist  chickens  or  small  pigs,  still 
stronger  fence  that  is  capable  of  turning  hogs/  cattle  and 
horses,  and  some  companies  now^  build  fence  that  will  turn 
Buffalo,  elk  and  the  iierce  lions  of  the  x\frican  frontier. 

But  the  post  question  has  not  been  so  successfully  an- 
swered. Wood  posts  are  becoming  scarce,  and  the  price  is 
constantly  going  up  while  the  qualit}^  and  the  size  of  the  posts 
are,  just  as  rapidly  going  down.  So  far  no  iron  posts  have 
been  built  which  are  sufficiently  cheap  and  strong  to  justify 
their  extensive  use  on  the  farm.  The  logical  solution  now 
seems  to  be  the  substitution  of  strongly  reinforced  cement 
posts  for  the  wooden  ones. 

Many  companies  have  built  molds  for  the  manufacture 
of  cement  posts.  These  molds  have  almost  invariably  molded 
a  post  which  does  not  contain  sufficient  cement  and  sand  to 
withstand  the  pressure,  no  matter  what  shape  or  form  was 
given  to  the  post.  Furthermore  no  matter  how  much  rein- 
forcement was  used  the  cement  could  not  stand  the  pressure. 
And  it  should  be  clearly  understood  that  the  reinforcement  in 
posts  should  be  of  iron  and  placed  in  the  corners  of  the  posts.. 
In  case  the  posts  must  resist  animals  upon  both  sides  of  the 
fence  the  posts  should  be  round  or  square,  not  of  the  triangular 


32 FARM  ENGINEERING 

type.  Wood  reinforcements  for  posts  are  not  satisfactory. 
The  wood  swells  and  bursts  the  post.  Then  it  shrinks  and  is 
loose  in  the  cement.  Some  salesmen  claim  that  water  cannot 
pass  through  the  cement  and  moisten  the  wood,  but  experi- 
ence does  not  support  the  theory. 

Some  companies  are  now  building  very  good  cement  posts 
but  the  cost  is  not  so  low  as  to  meet  the  competition  of  good 
wood  posts.  The  engineers  and  salesmen  of  many  companies 
set  up  the  claim  that  their  posts  are  strong  enough  to  with- 
stand the  wind  load  and  that  that  is  all  that  is  required.  Posts 
built  upon  this  theory  are  as  a  rule  not  sufficiently  strong  to 
provide  a  suitable  rubbing  post  for  a  small  cow.  Should  a 
hunter  climb  over  such  a  fence  he  almost  invariably  cracks 
the  post  upon  which  his  weight  comes.  This  kind  of  theoreti- 
cal design  has  put  the  cement  posts  into  disrepute  in  many 
localities.  The  claim  that  "Our  cement  post  is  as  strong  as 
any  wood  of  the  same  size,"  is  usually  not  backed  by  actual 
tests. 

"The  Bulletin  on  Concrete  and  Cement  Fence  posts,"  (Col- 
orado Bulletin  148),  by  H.  M.  Bainer  and  the  Author  of  this 
work  gives  the  results  of  actual  tests  with  both  Cement  and 
Concrete  fence  posts.  The  best  cement  and  a  good  grade  of 
sand  were  used.  The  posts  were  well  made  and  properly 
cured.  Yet  in  no  case  did  they  approach  in  strength  a  new 
wood  post  of  their  size.  As  this  bulletin  is  free  and  gives 
the  results  of  tests  on  several  hundred  cement  and  concrete 
posts,  the  student  should  by  all  means  avail  himself  of  the  in- 
formation. The  theory  of  the  reinforcing  material  and  the 
placing  of  it  in  the  post  is  thoroughly  taken  up  in  the  bulletin. 

There  is  no  doubt  that  a  very  good  concrete  or  cement 
post  can  be  built  which  will  last  longer  and  look  much  better 
than   the  wood   posts   which   are   now  being   sold. 

Setting  the  Posts. — There  is  no  rule  which  can  be  given 
as  to  the  depth  which  a  post  should  be  set.  In  some  soils  a 
post  need  not  be  set  more  than  18  inches  deep  while  in  others 
the  depth  must  be  from  3  feet  to  4  feet.     The  post  should  be 


FARM  ENGINEERING 


33 


set  sufficiently  deep  that  it  may  resist  a  side  thrust  sufficient 
to  break  it  at  the  ground  line. 

"How  strong  should  a  line  post  be?"  is  a  frequent  question. 

This  is  a  question  which  must  be  answered  according  to 
the  local  conditions.  A  post  which  projects  four  feet  from  the 
ground  should  stand  a  side  thrust  at  the  top,  of  at  least  300 
pounds.  This  is  less  than  a  3^"x3^"  new  spruce  post  will 
stand. 

Before  the  engineer  contracts  for  a  quantity  of  cement 
posts  he  should  test  several  samples  according  to  the  follow- 
ing directions:     (See  Plate  9.) 


>R^_-^t 


Plate  9.  The  drawing  Plate  9  shows  how  a  cement  post  may  be  tested. 
The  hitch  of  the  rope  a  is  just  4  ft.  above  the  ground,  b  is  an  easy 
running  pulley,  d  is  a  barrel  which  is  supported  above  the  scales, 
s.  c.  is  a  wooden  post  firmly  set  in  earth.  The  weight  of  barrel  plus 
the  water  which  must  be  added  to  break  the  post  is  the  breaking 
strength  of  the  post.  After  the  post  breaks  the  water  may  be  taken 
from  the  spigot  ^nd  used  in  the  testing  of  the  next  post.  Th ;  water 
should  be  added  slowly  until  post  breaks.  In  case  the  scale  platform 
cannot  be  held  off  the  knife  edges  which  it  rests  on  while  weighing, 
the  barrel  should  be  caught  by  a  cross  plank  and  let  slowly  down  to 
the  scales.  Many  other  pieces  of  apparatus  may  be  built  to  do  this 
testing. 

Corner  posts  and  gate  posts  must  be  much  stronger  than 
line  posts.  It  would  be  necessary  to  know  the  type  of  fence 
before  the  size  of  post  could  be  determined.     This  subject  is 


34 


FARM  ENGINEERING 


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FARM  ENGINEERING 35 

also    thoroughly    taken   up    in    the    cement    post    bulletin    above 
mentioned. 

Treatment  o£  wood  posts  to  lengthen  the  period  of  use- 
fulness. There  are  many  ways  in  which  a  wood  post  may 
be  treated  in  order  to  preserve  it.  Coal  tar  when  smeared 
upon  the  post,  from  the  ground  line  down  will  prevent  rot. 
A  good  oil  paint  will  also  do  good  work  as  a  preservative. 

If  an  iron  tank  is  available  it  is  a  good  plan  to  dip  the 
bottom  of  the  post  (up  to  4"  above  ground  line)  in  boiling  lin- 
seed oil.  But  the  cost  of  linseed  oil  is  such  as  to  make  this 
expensive.  Perhaps  the  most  effective  way  of  preserving  wood 
posts  is  by  means  of  the  creosote  treatment.  The  wood  is 
treated  under  pressure  with  creosote  and  this  renders  the  wood 
unfit  for  habitation  of  the  m3'-riads  of  tiny  insects,  fungi  and 
bacteria  which  cause  wood  to  decay.  This  treatment  requires 
expensive  apparatus  and  is  consequently  not  in  general  use 
so  far  as  fence  posts  are  concerned.  It  is  used  extensively  for 
the  treatment  of  railroad  ties  and  salt  water  piling. 

For  the  bracing  of  corner  posts  and  gate  posts,  see  draw- 
ing 10. 


BRIDGES   AND    CULVERTS. 

In  many  fields  we  find  creeks  and  ditches.  In  order  to 
cross  these  creeks  or  ditches,  some  farmers  resort  to  piling 
in  brush  and  then  covering  the  brush  with  manure  or  dirt. 
By  so  doing  they  often  cause  more  damage  to  be  done  than 
the  price  of  a  new  and  permanent  culvert  would  have  amounted 
to  in  the  first  place.  The  brush  culvert  is  likely  to  work  all 
right  for  a  while,  and  then  at  the  most  inopportune  moment 
it  may  break  down  or  clog  up,  and  the  surrounding  field  is 
inundated.  This  not  only  destroys  the  crops  but  it  is  likely 
to  cause  ditches  to  be  washed  in  the  land.  Another  point 
which  is  often  overlooked  is  the  fact  that  the  size  of  the  loads 
which  are  hauled  over  these  improvised  affairs  is  often  limited 
by  them.     The  teamster  often  unconsciously  lightens  the  load 


36 FARM  ENGINEERING ^ 

rather  than  run  the  risk  of  "sticking"  his  team  in  the  ditch. 
Again  the  fact  that  teams  of  young  horses  are  so  often  unable 
to  pull  through  these  ditches  causes  a  great  many  otherwise 
good  horses  to  be  balky,  and  consequently  next  to  useless. 
The  subject  of  Bridges  and  Culverts  will  be  taken  up  under 
Farm  Engineering  Part  III. 

It  should  be  mentioned,  however,  that  all  bridges  and  cul- 
verts should  be  made  strong  enough  to  carry  more  than  the 
load  to  which  the  hauling  of  grain  will  subject  them.  If  there 
is  any  possibility  that  a  threshing  machine  and  engine  will 
have  to  pass  over  the  bridge  it  should  be  designed  to  carry 
not  less  than  twenty-five  (25)  tons.  The  up-to-date  traction 
engines  are  being  made  larger  and  heavier  and  at  present  many 
have  passed  the  twenty-ton  mark. 

The  culverts  should  be  placed  where  they  will  give  the 
most  service  with  the  least  travel,  and  at  the  same  time  offer 
no  hindrance  to  the  free  flow  of  the  water  in  the  ditch  or 
creek. 

The  size  of  the  water-way  beneath  the  culvert  should  be 
large  enough  to  allow  the  water  to  pass  under  the  culvert, 
even  in  time  of  heavy  rains.  The  foundation  should  be  strong 
enough  to  prevent  the  washing  out  of  the  culvert  or  bridge 
by  swiftly  moving  flood  water,  or  the  jamming  out  of  the 
culvert  or  bridge  by  rapidly  moving  ice. 

In  order  to  properly  design  such  a  bridge  for  a  large 
stream  the  engineer  must  often  do  a  great  deal  of  field  work 
and  calculation.  But  for  the  smaller  creeks,  drainage  ditches 
and  irrigation  ditches  the  work  can  be  accomplished  by  the 
exercise  of  a  little  common  sense. 

In  case  the  bridge  must  span  a  mountain  torrent,  how- 
ever, there  is  need  for  care  no  matter  how  small  the  normal 
stream  may  be.  The  student  should  carefully  study  bridge 
and  culvert  design  in  Part  III  of  Farm  Engineering. 


FARxM  ENGINEERING 37 

DRAINAGE  AND  IRRIGATION. 

When  the  field  has  been  laid  out  and  fenced,  the  field 
engineering  work  is  by  no   means  complete. 

In  nearly  all  of  the  fertile  sections  of  the  United  States, 
and  in  fact  in  nearly  all  of  the  fertile  sections  of  the  globe, 
the  yield  of  desirable  crops  is  governed,  not  by  the  abundance 
or  scarcity  of  plant  food  in  the  soil  itself,  but  by  temperature 
and  moisture  conditions  in  the  air  and  in  the  soil. 

It  is  almost  impossible  to  influence  to  any  extent  the  tem- 
perature or  the  moisture  content  of  the_  atmosphere,  but  we 
can  govern  to  a  large  extent  the  moisture  content  of  the  sur- 
face layers  of  the  soil  to  a  depth  of  from  four  to  six  feet. 
The  principal  means  of  controlling  the  moisture  content  of 
the  soil  are : 

A.  Drainage. 

B.  Irrigation. 

C.  Combined  drainage  and  irriga,j:ion. 

D.  Scientific  cultivation. 

Drainage. — While  we  hear  a  great  deal  of  talk,  and  read 
a  great  many  well  written  articles  on  the  subject  of  irrigation, 
we  must  admit  that  the  greater  part  of  the  work  of  reclama- 
tion and  improvement  comes  under  the  head  of  Drainage.  No\ 
only  do  we  need  drainage  in  the  naturally  wet  lands,  but  in 
many  irrigated  sections,  drainage  must  be  resorted  to  in  order 
to  keep  the  soil  in  a  fit  condition  for  crop  production. 

Topography. — In  order  to  determine  the  lowest  or  the 
highest  portion  of  a  field,  the  grade  of  ditches  or  the  proper 
location  for  ditches,  either  drainage  or  irrigation,  we  must  be 
able  to  make  a  map  of  a  field,  which  will  show  just  what 
points  are  the  highest,  the  lowest,  and  what  points  are  on  a 
uniform  grade  from  the  highest  to  the  lowest. 

The  map  will  describe  not  only  the  boundaries  of  the  field, 
but  it  will  show  at  a  glance  the  "lay  of  the  land." 

1.  Stadia  Surveying. — This  is  done  by  means  of  a  transit 
and  a  stadia  rod.     The  three  cross  wires  of  the  transit  enable 


38 FARM  ENGINEERING 

the  surveyor  to  tell  how  far  the  stadia  rod  is  from  the  instru- 
ment. At  the  same  time  he  can  read  the  elevation  on  the 
rod  by  means  of  the  center  cross  wire.  He  then  reads  the 
vertical  circle,  and  by  higher  mathematics  the  exact  relative 
elevation  is  obtained. .  This  method,  when  used  by  experi- 
enced survej'ors  enables  them  to  make  rapid  progress  in  the 
work,  but  the  work  when  completed,  is  not  absolutely  accur- 
ate. In  the  preliminary  work  of  railroad  location,  or  in  the 
running  -of  large  canals  for  long  distances,  it  is  a  very  good 
method  of  mapping  the  contour  of  the  land.  Then,  after  the 
map  is  made,  the  railroad  or  the  ditch  may  be  located  on  the 
map  and  later  on,  it  may  be  laid  out  in  the  field.  As  stadia 
work  is  not  necessary  for  ordinary  field  engineering,  no  fur- 
ther attention  will,  be  given  it  here, 

2.  Level  and  Rod  Surveying. — The  surveyor's  level  and 
rod  may  be  used  intelligently,  easily,  and  very  accurately  by 
anyone   who   understands    plain,    ordinary    Arithmetic, 

Before  going  into  the  field,  the  engineer  should  see  that 
his  level  is  in  adjustment.  Do  not  guess  at  this.  Do  not  as- 
sume that  the  maker  has  adjusted  the  instrument  before  send- 
ing it  out.  Beyond  a  doubt  the  instrument  was  in  adjustment 
when  it  left  the  factory,  but  a  railroad  journey  often  puts  a 
level  out  of  adjustment.  If  the  level  sets  in  its  case  or  on 
the  tripod  during  a  rough  wagon  journey,  it  is  likely  to  be 
put  out  of  adjustment.  Be  sure  of  the  adjustments  before  you 
begin  to  "Run  Levels"  over  your  field.  The-  few  minutes  of 
time  required  to  check  adjustments   are   always  well   spent. 

The  Philadelphia  Rod  is  one  of  the  most  satisfactory 
levelling  rods  for  the  Agricultural  Engineer.  (See  Plate  3, 
Fig.  4.)  Do  not  make  the  mistake  of  thinking  :  that  only  an 
Architect's  rod  will  work  with  an  Architect's  level.  This  is 
not  the  case.  The  Philadelphia  Rod  reads  to  feet,  tenths  of 
feet,  and  hundredths  of  feet  without  the  use  of  the  target, 
while  by  using  the  target  we  may,  (by  means  of  the  Vernier) 
read  to  thousandths  of  a  foot. 

Now  that  we  have  a  properly  adjusted  level,  and  a  suit- 
able   rod,   we   will   proceed   to    run    levels   over   a    certain    field. 


FARM  ENGINEERIKi; 


39 


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40 


FARM  ENGINEERING 


We  will  assume  that  the  field  is  uneven,  but  that  it  has  a 
very  apparent  slope  towards  one  corner.  It  is  apparent  that 
the  outlet  of  the  drainage  system  must  be  at  the  lowest  point. 
The  engineer  first  drives  a  stake  (a  solid  one)  into  the  ground 
until  its  top  is  level  with  the  surface  of  the  ground,  at  the 
assumed  point  of  outlet. 

The  level   is   set   up  some   distance    (50  to  200  ft.)    away, 


N 

A 


Sco/e  /D/fo</S  Perlfich 


Plate  12.  The  map,  Plate  12,  shows  how  the  -surveyor  began  at  the  point 
o  and  ran  levels  over  the  field  to  get  a  fair  idea  of  the  relative  eleva- 
tion of  the  different  points.  The  statoins  are  numbered  in  order  as 
he  proceeded.  He  was  not  very  careful  about  Stations  10,  11  and 
12  as  the  knoll  or  Iiill  was  very  apparent.  He  made  a  rough  sketch 
of  the  land  as  he  went,  and  by  the  aid  of  the  elevations  of  the  Station 
6,  he  was  able  to  make  a  sufficiently  accurate  topography  map.  He  then 
plotted  in  a  ditch  with  but  one  bend,  laid  it  off  in  100  ft.  stations  and 
ran  a  line  of  levels  up  the  ditch,  establishing  grade  and  cut  as  he 
went.  The  ditch  is  800  ft.  long  and  the  difference  in  elevation  between 
o  and  17  is  approximately  3  ft.  (12.95 — 10z=2.95).  3h-8=.375  ft.  per 
hundred  ft.  He  decides  upon  2  ft.  as  the  depth  of  the  ditch. 
10'— 2 '=8'  the  grade  of  the  ditch  at  o.  At  Station  100'  the  grade 
will  be  8'  plus  .375  or  8,375'.  At  each  succeeding  station  he  adds 
.375  ft.  to  the  height  of  the  preceding  station.  Thus  the  bottom 
of  the  ditch  is  on  even  grade.  He  also  determines  the  cut  by  sub- 
tracting the  grade  from  the  elevation  at  each  station. 


FARM  ENGINEERING ^ 41 

and  the  rod  is  placed  upon  the  newly  driven  stake.  The  stake 
will  be  known  as  the  "Bench  Mark."  We  usually  assume  that 
its  elevation  is  ten  feet.  After  the  level  is  firmly  set  and 
levelled,  the  engineer  looks  through  the  level,  and  after  hav- 
ing directed  the  rodman  to  hold  the  rod  perfectly  vertical,*  he 
carefully  reads  the  number  of  feet,  tenths  and  hundredths 
which  the  cross  wire  indicates  on  the  distant  rod. 
of  sight  from  the  level  to  the  rod  is  level. 

The  reading  is  added  to  the  original  (assumed)  10',  and 
the  total  recorded  as  the  "height  of  instrument"  (H.  I.).  The 
reading  of  the  rod  is  recorded  as  the  "Back  Sight"  (B.  S.).  Do 
the  recording  at  once  with  a  hard,  smooth,  pointed  pencil. 
(See  specimen  notes,  Plate  13.) 

Now  it  is  apparent  that  the  center  of  the  level  lens  is 
just  as  many  feet,  tenths  and  hundredths  above  the  top  of 
the   "Bench  Mark"   as  the   reading  indicates,   because   the   line 

Now  the  rodman  changes  location  and  places  the  rod  upon 
the  ground.  The  level  is  turned  so  as  to  bear  upon  the  rod 
and  another  reading  is  taken. 

The  "Bench  Mark"  is  designated  as  Station  0  (zero),  and 
the  new  station  is  called  Station  1.  Whatever  the  reading  of 
Station  1  happens  to  be,  it  is  recorded  under  foresight  (F.  S.), 
and  this  subtracted  from  the  H.  I.,  will  give  t^e  relative  eleva- 
tion of  Station  1.  The  elevation  is  computed  and  recorded 
in  the  column  under  elevation  (Elev.)  and  on  the  line  given 
to  Station  1. 

The  student  will  not  notice  that  if  the  F.  S.  reading  is 
greater  than  the  B.  S.  reading,  station  1  is  lower  than  0,  and 
that  if  the  reading  is  less  than  the  B.  S.  reading,  station  1  is 
higher  than  station  0.     This  point  often  fools  the  beginner. 

Again  the  beginner  often  imagines  that  the  height  of  in- 
strument   is    obtained   by    measuring    from    the    center    of    the 


*  The  vertical  wire  enables  the  engineer  to  see  whether  or 
not  the  rod  is  being  correctly  held.  The  rod  should  "line  up" 
with  the  vertical  wire. 


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Plate  13.  The  notes  shown  in  Plate  13  are  the  notes  which  the  engineer 
took  in  mapping  the  ten  acre  field  of  Mr.  T.  Jones  shown  in  Plate 
12.  Notice  that  Station  O  is  given  an  assumed  elevation  of  10'.  This 
is  done  so  that  if  a  lower  point  is  found  it  will  not  have  a  "Minus 
•IcTation."  The  three  dots  inside  a  circle  indicate  Avhere  the  level 
was  set  up.  Notice  that  it  is  not  over  a  station.  By  going  over  the 
map  one  can  trace  the  movements  of  the  engineer  as  he  proceeded 
,  up  the  field.  The  student  will  notice  that  a  Foresight  is  not  neces- 
sarily on  the  opposite  side  of  the  instrument  from  the  station  upon 
which  the  Baclssight  was  taken.  The  stations  may  be  within  a  foot 
of  each  other,  but  the  one  with  the  Jcnoivn  elevation  is  used  for  the 
back  sight  while  the  one  with  the  unknoion  elevation  calls  for  the 
Foresight.  The  above  process  is  known  under  the  term  of  Differential 
Leveling.  The  length  of  the  Backsight  and  the  Foresight  to  the 
turning  point  should  be  nearly  the  same  distance.  This  must  be 
remembered  or  errors  are  lilrely  to  creep  in.  It  is  not  necessary  if 
thie  instrument  is  in  perfect  adjustment. 


FARM  ENGINEERING 43 

tube  to  the  ground.  This  is  not  the  case.  The  height  of  the 
instrument  is  the  distance  which  it  is  higher  than  the  eleva- 
tion of  the  station  upon  which  the  last  backsight  was  taken. 

The  engineer  is  now  able  to  "prospect"  for  a  lower  point 
of  outlet  for  the  drain.  If  it  is  found,  he  marks  the  place  and 
turns  his  attention  to  the  rest  of  the  field.  When  he  has  taken 
a  reading  with  the  rod  about  as  far  up  the  field  from  the  in- 
strument, as  the  0  station  was  down  the  field  from  the  instru- 
ment, he  signals  the  rodman  to  "hold  the  point."*  He  then 
proceeds  to  pick  tip  the  level  and  go  to  a  point  some  distance 
beyond  the  rodman,  sets  up  his  level,  and  sights  back  at  the 
rod.  The  reading  is  recorded  under  column  B.  S.,  and  on  the 
line  given  to  the  last  station.  Now,  by  adding  the  B.  S.  read- 
ing to  the  elevation  of  the  last  station,  (which  the  rodman 
is' "holding-"),  the  new  height  of  instrument  is  obtained. 

More  foresights  are  taken  and  the  elevation  of  the  new 
stations  obtained.  In  this  way  the  engineer  proceeds  to  get 
the  elevation  of  the  chosen  points.  (Not  the  elevation  above 
sea  level,  but  the  elevation  above  the  bench  mark.)  Now  he 
can  figure  out  how  much  grade  (drop  or  rise)  per  hundred 
feet  he  has,  and  where  he  will  locate  the  drain. 

i)uppose  that  in  a  proposed  drain  of  4620  feet  he  finds  that 
the  total  fall  is  17'  and  3"  (seventeen  and  three-tenths  feet). 
He  divides  the  drain  into  100  foot  stations  and  thus  finds 
that  he  has  46  1^5  stations. 

If  the  grade  is  uniform,  he  divides  the  total  fall  into  46 
parts  (ignoring  the  1/5  station)  and  finds  that  he  may  give 
each  100'  of  the  drain  17.3"^  46  or  .376  of  a  foot  fall  to  the 
,  hundred. 

He  now  decides  on  the  depth  of  his  drain  at  the  outlet, 
and  if  the  depth  is  the  same  at  the  head  of  the  drain,  he  is 
now  ready  to  compute  the  elevation  of  the  bottom  of  the 
ditch  at  each  100  ft.  station. 


*  The  rodman  must  make  sure  that  he  does  not  sink  the 
rod  into  the  ground  or  raise  it  after  the  last  F,  S,  is  taken 
until  the  new  B.  S.  is  read.  The  station  is  known  as  the 
"Turning  Point,"  T.  P. 


44 


FARM  EiNGINEERING 


Starting-  at  0  he  subtracts  the  depth  of  the  drain  from  the 
elevation  of  0  (IC  was  assumed)  and  adds  to  this  reading  the 
.376  foot  for  each  station  above.  By  continuing  to  add,  he  ob- 
tains the  elevation  of  the  bottom  of  the  ditch  at  each  station 
of  the   ditch. 

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Plate  14.  Plate  14  is  a  page  (33)  of  an  engineer's-  note  boolv.  It  shows 
Jiow  lie  laid  out  the  ditch  after  the  Topography  map  had  been  roughly 
made.  He  laid  out  his  grade  and  then  recorded  the  "cut"  as  he  went 
along.  The  figures  should  be  made  with  a  hard  lead  pencil,  so  that 
they  will  appear  neat  and  remain  plain.  (For  Engineers'  pocket  field 
books  see  Frederick  Post  Catalogue.)  Select  what  you  xcant  before 
ordering.     See  also  Eugene  Dietzgen  catalogue. 

He  then  proceeds  to  lay  off  his  station  points  with  a 
tape.  A  stake  is  driven  into  the  earth  and  the  number  of 
the  station  is  plainly  written  on  the  stake  with  a  crayon  or 
soft  pencil.  These  stakes  locate  the  ditch.  Now  at  a  distance 
of  2,  3,  or  4  feet,   (depending  upon  the  size  of  the   ditch)    to 


FARM  ENGINEERING 


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FARM  ENGINEERING 


one  side  of  each  stake  is  placed  another,  the  guide  stake.  This 
is  done  so  that  the  location  of  the  first  is  not  lost  in  case  it 
is  knocked  over.  The  engineer  now  goes  over  the  ground 
wiLh  the  level  and  rod  and  by  subtracting  the  computed  ele- 
vation of  the  bottom  of  the  ditch  frorn  the  elevation  of  the 
top  of  the  ditch  stakes,  (he  obtains  these  elevations  as  he 
goes,  by  reading  the  rod  when  placed  upon  the  stakes),  he 
obtains  the  depth  of  the  ditch  below  the  top  of  .the  stake.  He 
then  writes  "the  cut"  on  each  stake.  "The  cut"  is  the  depth 
which  the  ditch  must  be  "cut"  or  dug  below  the  top  of  the 
stake. 

"*  When  the  levels  are  all  taken,  the  cuts  determined,  and 
the  width  of  the  ditch  decided  upon,  stakes  are  driven  beside 
th  ditch.  Then  a  notch  is  sawed  in  the  side  of  each  stake  a 
certain  distance  above  the  bottom  of  the  ditch.  A  heavy 
string,  or  what  is  better,  a  fine  wire  (No.  15  or  16)  is  drawn 
tight  along  the  ditch.  It  is  tied  into  each  notch  and  if  the 
,  ditch  is  on  even  grade,  the  wire  will  be  straight  when  tied  in. 
The  ditch  digger  needs  only  to  gauge  the  bottom  of  his  ditch 
from  the  wire  and  this  is  easily  done  by  means  of  a  "gauge 
stick." 


/^ 


11"  '  „! 


S 


\ 


Plate  1(5.  Plate  16  sIioavs  a  side  view  of  two  "gauge  sticlis."  Fig.  A 
is  of  a  stick  used  tor  narrow  ditclies  and  as  tlie  side  arm  is  short  the 
digger  is  able  to  hold  the  stick  nearly  plumb  and  thus  get  the  ditch 
on  even  grade. 

Fig.  B  is  of  a  stick  for  wider  ditches.  There  is  a  carpenter's  level 
fastened  to  the  top  of  the  cross  arm  and  the  stick  is  so  held  that  the 
bubble  comes  to  center.  The  student  can  readily  see  how  the  use 
of  the  string  stretched  an  exact  distance  above  the  bottom  of  the 
ditch,  and  one  of  these  gauge  sticks,  will  enable  a  digger  to  get  an 
even  grade. 


FARM  ENGINEERING 


47 


"J'he  stakes  which  hold  the  wire  need  not  1)e  set  at  inter- 
vale of  less  than  25  feet.  In  case  of  string,  they  should  be 
set  ever}^  10  feet. 

When  the  ditch  is  dug,  the  engineer  should  run  levels  on 
it  A\'ith  the  rod  set  on  the  bottom  of  the  ditch  at  frequent 
intervals    (ever}^    10,   IS   or  20  ft.).     In   this   Avay   he   can   make 


Plate  17.  When  the  engineer  began  work  on  the  ten  acre  flelrl  in  Plate  17 
he  found  that  the  field  was  nearly  level.  He  began  at  the  S.  W. 
forner  and  ran  lines  of  levels  North  and  South  at  intervals  of  100'. 
He  made  his  stations  100  feet  apart.  The  narrow  "left  over"  was  at 
the  North  side  and  the  East  side.  When  he  had  finished  he  drew 
a  map  and  giving  station  at  S.  W.  corner  an  elevation  of  10'  he  pro- 
ceeded to  write  the  elevation  of  ■  each  station  at  the  intersection  of 
the  hundred  foot  lines.  Then  he  was  able,  to  draw  in  the  contour 
lines.  He  found  the  point  X  to  be  lowest,  but  he  Jiad  less  than  a 
foot  of  fall  in  that  direction.  If  he  could  get  an  outlet  near  X  then 
he  could  by  dcepeniiu/  the  lower  portion  of  the  ditch,  drain  the  field. 
Xow  suppose  that  a  deep  ravine  runs  along  one  of  the  other  sides  of 
the  field.  The  engineer  can  drain  this  field  to  the  East,  North,  or 
South,  by  using  a  shallow  drain  near  X  and  deepening  it  enough  to 
cut  the  banks  near  Y  or  Z.  This  is  not  an  exaggerated  case.  Many 
fields  give  the  engineer  more  trouble  than  this  one.  If  a  "cross 
section"  paper  has  been  used  for  the  map  the  lines  might  have  been 
more  accurately  drawn,  but  they  would  not  have  developed  any 
outlet,  or  higher  grade.  (For  cross  section  paper  see  Frederick  Post 
catalogue. ) 


FARM  ENGINEERING 


sure  that  the  stakes  and  line  were  not  molested,  and  that  the 
ditch   is   properly   dug. 

Method  for  Nearly  Level  Fields. — In  case  of  fields  which 
are  nearly  level,  the  work  must  be  done  with  more  attention 
to  detail.  It  is  best  to  run  parallel  lines  of  levels  about  100 
feet  apart.  The  stations  should  not  be  more  than  100  feet 
apart.  Thus  the  field  is  divided  into  a  series  of  100  feet 
squares.  (Checkerboard  style.)  When  the  exact  elevation 
of  each  station  is  obtained,  draw  map  and  put  in  the  contour 
lines  on  each  1/10  ft.  (Ten  lines  to  1  ft.  elevation.)  The  lines 
now  show  the  lay  of  the  land.  The  drain  can  be  plotted  on 
the   map,   and   laid  off  in  the   field. 

When  the  drains  have  been  located,  the  engineer  should 
indicate  on  his  map  the  number  of  degrees  each  bend  throws 
the  ditch  from  the  straight  line.  He  should  also  show  the 
distance   from  each  bend  to  the   next  bend. 

The  drain,  near  its  foot,  will  form  an  angle  of  a  certain 
number  of  degrees  with  a  line  fence,  a  road,  or  a  section  line. 
This  angle  must  also  be  recorded.  Thus,  a  person  who  later 
wishes  to  know  how  the  drain  runs,  has  only  to  consult  the 
map.  In  case  of  hidden  tile  drains,  the  map  is  of  great  im- 
portance. 

The  angle  between  the  ditch  and  some  permanent  line 
should  always  be  used,  rather  than  the  compass  bearing.  Com- 
passes vary,  and  the  North  Magnetic  Pole  also  varies,  but  a 
section  line  is  finally  established. 

Change  of  Grade. — Sometimes  the  land  lies  so  that  it  is 
impossible  to  run  the  ditch  on  "even  grade,"  that  is,  with  the 
same  fall  to  each  100  ft.  In  such  a  case  we  "change  grade," 
but  whenever  it  is  possible  the  grade  should  grow  greater  (or 
steeper)  as  we  proceed  down  the  ditch.  If  the  top  of  the 
ditch  is  steep,  and  the  change  causes  the  water  to  flow  into 
a  more  nearly  level  ditch,  the  water  will  not  be  carried  away 
fast  enough,  and  there  will  be  flooding  at  the  point  of  change. 
If  the  lower  ditch  is  made  larger,  it  will  take  care  of  the 
water,  but  the  water  will  flow  slower  in  the  large  ditch  of 
less  grade. 


FARM  ENGINEERING 


49 


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FARM  ENGhNEERIKG 


Rio-lit  here  the  student  must  know  that  the  faster  water 
flows,  the  greater  the  size  of  soil  particles  it  will  carry.  Sand 
nnll  settle  out  of  slowlv  moving  water,  while  larger  stones 
ire  carried  along  by  a  torrent. 

So,  when  the  swiftly  moving  water  of  the  upper  ditch  of- 
high  grade  comes  into  the  larger  ditch  of  lower  grade,  the- 
water  slows  down,  and  deposits  sand  and  silt  in  the  ditch 
bottom..  This  soon  fills  up  the  ditch  or  tile  and  the  ditch 
proves  a  failure.  But,  if  the  grade  of  the  ditch  be  increased 
rather  than  decreased,  the  water  gains  speed,  and  there  is  no 
tendency  to  fill  up  the  ditch  with  deposits  of  sand  or  silt.  If 
it  is  absolutely  necessary  to  change  the .  grade  of  the  lower 
part  of  the  ditch  to  a  lower  grade,  the  point  of  change  of 
grade  should  be  carefully  watched. 


f  ^ 


Plate '19.  Plate  19  is  a  cross  section  of  a  "silt  basin."  Viewing  the  basin 
from  the  top  it  would  appear  round.  It  \YOuld  be  simply  a  shallow 
round  well  loosely  walled  up  with  brick  or  stone  or  perhaps  with  a 
concrete  wall  about  4  inches  thick.  The  tile  comes  in  at  one  side. 
The  water  is  r-lowed  up  and  as  it  slowly  flows  across  the  well  or 
basin  the  silt  and  sand  settles  to  the  bottom.  The  water  passes  out 
the  other  side  into  the  tile  of  lower  grade.  If  the  basin  had  a 
grated  top  and  were  a  little  lower  in  the  ground  it  would  be  a 
"Catch  Basin"  or  "Sumj)."  The  water  mignt  then  enter  from  the  top. 
The  Arrow  shows  the  direction  of  flow. 

In  case  of  tile  drains,  a  "silt  basin,"  see  Plate  19,  should 
be  placed  at  the  point  of  change  of  grade.  This  may  be 
cleaned  out  from  time   to   time. 

So-called  "practical  ditchers"  will  tell  the  engineer  that 
this  is  not  necessary,  but  after  the  credulous  engineer  spends 
a   few   days  locating   a   tile   drain   that  has   not  been   mapped. 


FARM  ENGINEERING ^i 

and  is  now  useless,  digs  up  the  tile,  and  pokes  the  solid  sedi- 
ment from  the  clog',§"ed  tile  with  a  stick,  and  finds  in  many 
places  that  the  tile  has  been  completely  clogged  by  deposited 
sediment,  he  will  realize  that  the  laws  of  Nature  AA^ork  exactly 
the  same  whether  the  engineer  sees  the  process  or  not.  Such 
an  experience  will  do  more  to  instill  a  true  appreciation  of 
the  effect  of  change  of  grade  in  ditches,  into  the  mind  of  a 
student  than  a  volume  of  sermons  upon  the  suliiect. 

If  the  student  wishes  to  take  up  the  work  of  tile'  drain- 
ing, he  should,  if  convenient,  procure  '"Engineering  for  Land 
Drainage,"  by  -Elliot,  from  John  Wiley  &  Sons,  New  York. 
This  large  volume  contains  all  detailed  information  which  the 
engin.eer  will  need.     It  is  reliable. 

Oirdets  of  Drains. — .It  is  usually  advisable  to  wall  up  the 
outle;;s  of  drains  to  prevent  the  washing  away  of  the  adjoin- 
ing land.  In  case  of  tile  drains  a  cross  wall  should  be  built 
so  that  the  tile  projects  through  the  wall.  There  should  be  a 
chance  for  the  water  to  flow  freely  away  from  the  mouth  of 
the   tile. 

Drainage  by  Pumping  Plants. — In  Holland,  the  drainage 
water  is  lifted  over  the  protecting  dykes  by  large  windmills, 
(the   Dutch   windmills  we   so  often   see   in  pictures). 

in  this  countrv,  the  steam  engine,  the  gasoline  engine,  and 
the  electric  motor  are  now  being  used  in  connection  with  cen- 
trifugal yumps  to  raise  drainage  water  from  low  lands  and 
throw  it  into  a  drain  which  is  higher  than  the  land  itself.  See 
Eidletin  2^.3..  U.   S'.   Deut.  of  Agriculture. 


DIGGING   THE   DITCHES. 

The  co-dition  of  the  earth,  the  kind  of  soil,  and  the  rela- 
tive cost  of  labor,  V'ill  determine  largeh^  the  methods  lo  be 
employed   in   digging  the   ditches. 

Immense  plows,  drawn  by  capstans  are  often  used  for 
open   ditches.      .A   quicker  way   is   to   place    sticks   of   dynamite, 


52 


FARM  ENGINEERING 


Plate  20.  Plate  20  is  an  instantaneous  photo  of  a  dynamite  explosion 
which  dug  200  feet  of  ditch  in  about  ten  seconds.  The  sticks  of  75 
per  cent  dynamite  weight  ^  lb.  each  and  were  placed  two  feet  apart 
in  holes  three  feet  deep.  The  ditch  is  about  tour  feet  deep.  It  is 
about  two  feet  wide  at  the  bottom  and  four  feet  wide  at  tlie  top. 
The  man  who  shot  the  charge  and  the  photographer  were  under  a  loau 
of  straw,  200  feet  away.  Rocks  the  size  or  a  man's  head  flew  as 
much  as  400  feet  from  the  ditch.  The  ditch  was  left  smooth,  straight 
and  in  fine  condition  without  any  further  labor. 

(at   least   75%    strength)    in   holes   about   two    feet   apart    along 

the  line  of  the  ditch.     By  means  of  an  electric  current  all  the 

sticks  are  set  off  at  once.     The  earth  is  blown  from  the  ditch 

and    falls    upon    the    banks    and    in    the    nearby    fields.      A    half 

mile   of   ditch   is   sometimes   made   at   a   single    explosion.      For 

information    (free)    write    to    E.    I.    Dupont    Co.,    Wilmington, 

Delaware. 

A  great  many  ditching  machines  are  now  built  by  various 

companies.     These  machines  dig  the  ditch  by  means  of  steam 


FARM  ENGINEERING 53 

or  gasoline  power.     They   are   successful   under   favorable   con- 
ditions. 


IRRIGATION. 

We  have  discussed  the  method  by  which  we  are  able  to 
reduce  the  moisture  content  of  the  soil,  now  let  us  consider 
how  Vv^e  may  increase  the  moisture  content.  A  few  years  ago 
we  might  have  been  led  to  believe  that  the  so-called  "Rain 
Makers"  could,  by  the  explosion  of  bombs  at  high  elevations, 
cause  rain  to  fall  at  will.  Now  we  have  definitely  settled  upon 
Irrigation  as  the  system  which  must  be  used  if  we  are  to  add 
water  to  the  soil  by  artificial  means. 

Irrigation  has  been  practiced  for  many  hundreds  of  years 
in  some  of  the  older  countries.  It  is  now  being  practiced  in 
the  United  States,  both  on  semi-arid  lands  and  the  lands  of 
the  humid  sections.  In  fact,  the  sprinkling  of  a  lawn,  or  the 
watering  of  garden  truck  is,  in  a  way,  irrigation.  But,  as  the 
Agricultural  Engineer  considers  irrigation,  the  term  refers  to 
the  addition  of  great  quantities  of  water  to  tracts  of  consider- 
able  size. 

Sources  of  Irrigation  Water. — Rivers  are  the  principal 
sources  of  irrigation  water.  The  water  is  diverted  by  dams 
into  ditches  and  thus  conveyed  to  the  fields,  or  to  storage 
reservoirs.  The  rights  to  use  water  from  these  rivers  are 
secured  by  legal  process,  and  when  once  secured,  are  valuable 
property.  The  amount  of  water  which  may  be  secured  for  a 
certain  tract  of  land  is  usually  limited  b}^  law.  The  student 
must  look  up  these  matters  for  himself,  as  the  State  lavvi 
vary  so  much  that  no  exact  data  can  be  given  in  this  work. 

After  all  the  water  available  during  the  irrigation  season 
has  been  appropriated,  companies  are  formed  for  the  purpose 
of  building  storage  reservoirs.  By  placing  a  dam  across  some 
narrow  outlet  to  a  large  natural  basin,  a  lake  is  formed.  The 
river  water  is  then  diverted  into  a  ditch  which  leads  to  the 
reservoir.     The  water  is   stored   during  the   winter   season   and 


54 


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FARM  ENGINEERING 55 

at  the  time  of  floods. 

The  water  remains  in  the  reservoir  until  needed  for  irri- 
gation. The  size  of  these  reservoirs  varies  from  a  few  acres 
to  several  square  miles.  Sometimes  natural  lakes  are-  tapped 
by  ditches  and  they  then  become  reservoirs.  The  outlet  of  a 
reservoir  is  governed  by  a  headgate,  such  as  is  shown  in  Plate 
21.  These  headgates  are  often  large  enough  to  open  a  hole 
four  feet  square.  In  some  cases,  several  gates  are  placed 
side   by  side. 

If  the  student  will  imagine  water  under  a  head  of  20  or 
30  ft.,  spouting  from  two,  three,  or  four  of  these  great  head- 
gates,  he  will  get  an  idea  of  the  immense  amount  of  water 
which  some  of  these  ^vater  storage  companies  use  on  the  fields 
beiow  the  reservoir. 

RiA'er  water  is  o?tcn  pumped  to  land  which  lies  at  a 
height  which  makes  it  impossible  to  bring  the  water  to  the 
land  b}'  ditclies.  These  plants  are  much  like  the  drainage 
plants  except  that  the  water  is  pumped  into  large  flumes  and 
carried  to  the  fields.  Sometimes  the  cost  of  a  flume  would  be  . 
so  great  that  the  "Inverted  Siphon"  is  used.  This  consists 
of  a  v\'ater-tight  pipe  with  the  ends  bent  up  until  the  intake 
end  is  high  enough  to  cause  water  pumped  in  at  this  end  to 
run  out  the  outlet  end.  Again  we  sometimes  see  the  pump 
directly  connected  to  a  pipe  which  runs  up  the  hill  side  to  the 
higlier  ground. 

Wells. — In  some  parts  of  the  country,  the  land  is  under- 
laid with  a  "stratum  of  water  bearing  gravel  or  sand.  If  this 
stratum  is  within  40  to  50  feet  of  the  surface,  and  if  it  carries 
water  in  suflicient  quantity,  a  pumping  plant  may  be  used  for 
irrigation.  The  wells  are  usually  large  in  diameter  (12  to  20 
feet).  The  casing  must  allow  the  water  to  pour  in  without 
difnculty.  By  the  proper  installation  of  the  right  kind  of  ma- 
chinery, these  wells  are  made  to  be  excellent  sources  of  irri- 
gation water. 

Do  not  confuse  a  well  of  this  kind  with  a  small  farm  well 
whicli  has  a  capacity  of  }4    cubic   foot  per  minute.     Some  of 


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Plate  24.  In  order  to  understand  Plate  24  the  student  must  imagine  tlaat 
tlie  shed  of  tlie  pumping  plant  has  been  cut  by  a  plane  which  passes 
t'M-ough  the  ridge,  the  ends  and  the  soil  beneath  the  plant.  The  plane- 
does  not  cut  the  engine,  the  pump  frame,'  or  the  flume.  The  engine 
sets  on  a  concrete  foundation  and  is  fastened  by  anchor  bolts.  The 
Gasoline  tank  is^  outside  the  building  and  is  covered  by  a  box.  The 
suction  and  overflow  pipes  run  from  engine  to  tank.  (No  cooling 
device  is  shoAvn.)  The  well  is  large,  and  is  cased  with  rough  planks 
which  allow  water  to  flow  through  readily.  The  pump  is  of  the 
Vertical  centrifugal  type  and  is  fastened  in  a  frame  which  slides  in- 
side the  frame  which  we  see.  If  the  operator  wishes  to  fix  the  pump 
he  attaches  the  tackle  (suspended  from  the  roof)  to  the  loop  on  th« 
frame  and  after  having  loosened  the  pipe  elbow  he  arises  the  inside 
sliding  frame,  with  pump  attached,  until  the  pump  comes  to  the 
platform  half  way  down  in  the  well.  He  then  makes  repairs,  drops 
the  pump,  connects  el1>ow,  puts  on  the  holt  and  goes  ahead.  As  this 
type  of  pump  is  alwavs  in  the  water  it  is  alicays  primed.  If  the  belt 
is  cropsed  the  wrong  way  little  or  no  water  is  pumped.  The  student 
must  remember  to  run  the  centrifugal  pump  in  the  rif/Jit  direction. 
Notice  that  the  pipe  is  enlarged  just  above  the  pump.  It  is  thus  made 
easier  for  the  pump,  the  engine  and  all  connections.  The  enlarging 
of  the  pipe  reduces  friction  and  thus  saves  gasoline.  The  end  of 
the  flume  is  seen  at  the  left  of  the  pumphouse.  If  a  ditch  or  creek 
emptied  water  into  the  well  it  would  then  be  termed  a  "Sump." 


FARM  ENGINEERING 59 

these   wells   furnish   as   much    as   three   or   four   cubic    feet   per 
second. 

Amount  of  Water  Needed. — It  is  generally  considered  that 
water  to  a  depth  of  from  one  to  two  and  one-half  feet  must 
be  added  in  order  to  properly  irrigate  the  average  soils.  The 
amount  varies  with  the  amount  of  rainfall  during  the  growing 
season,  the  temperature  of  the  locality,  the  amount  of  wind, 
the  type  of  soil,  and  the  kind  of  crop  to  be  grown.  So  we 
see  that  no  hard  and  fast  rule  can  be  laid  down,  which  will 
determine    the    amount   of  water   needed. 

Units  of  Measure  for  Irrigation  Water. — There  are  many 
units  of  measure  for  irrigation  water.  Many  of  these  units 
are  not  standardized,  and  are,  therefore,  unreliable  units. 

The  "miner's  inch"  refers  to  the  amount  of  water  which 
will  pour  through  an  opening  one  inch  square  in  the  side  of 
a  box,  when  under  a  head  of  six  inches.  But  whether  the 
head  is  to  be  measured  from  the  top  of  the  opening  or  the 
bottom  is  not  generally  stated.  Therefore,  the  actual  head  is 
an  unknown  quantity  and  the  quantity  of  water  which  rep- 
resents  a  miner's   inch  is  unknown. 

The  "inch."  This  is  a  term  that  completly  fools  many 
people.  It  may  mean  one  inch  of  water  covering  an  area  of 
one  acre.  It  may  mean  the  amount  of  water  which  will 
flow  over  a  weir  one  feet  wide,  with  a  depth  of  one  inch  at  the 
crest.  It  may  mean  a  "miner's  inch."  It  may  mean  almost 
-anything,  and  yet  people  talk  about  the  "inch"  of  water  as 
though  they  really  knew  what  the  term  really  means.  No 
more   space  will   be   given  to  inaccurate   units. 

Accurate  Units. — The  cubic  foot  per  second.  This  unit  is 
.accurate  because  a  cubic  foot  is  a  cubic  foot  and  a  second  is 
a  second.  Both  are  standard  units.  So  when  a  man  says,  "1 
own  three  cubic  feet  per  second  for  a  90-day  season,  beginning 
June  1st,"  we  could  figure  just  how  many  cubic  feet  of  water 
he  has  a  right  to  use  each  year. 

60  X    3=180  cubic  feet  per  minute. 
180  X  60=10,800  cubic  feet  per  hour. 


6o 


FARM  ENGINEERING 


Plate  25.  The  engineer  in  Plate  25  is  measuring  the  flow  of  water  in 
the  canal  by  means  of  a  current  meter.  There  is  a'  turbine  wheel 
at  the  end  of  the  tube  which  he  is  holding.  This  wheel  whirls  at 
a  speed  in  proportion  to  the  rate  of  flow  of  the  water.  As  the 
wheel  revolves  it  is  made  to  give  a  clicking  sound  which  is  heard 
through  the  tube.  The  number  of  clicks  per  minute  is  taken  and 
then  by  consulting  a  chart  which  accompanies  the  meter  the  observer 
is  able  to  determine  the  rate  of  flow  of  the  various  parts  of  the  current. 
The  engineer  in  the  plate  is  using  an'  "Acoustic  Current  Meter." 

10,800  X  24=259.200  cubic  feet  per  day. 

259,200  X  90=^23,280,000  cubic   feet   per   season. 

The  Acre  Foot. — We  often  use  the  term  "acre  foot,"  and 

by  it  we  mean  that   quantity  of  water   which   will   cover   one 


FARM  ENGINEERING  6t 

— — J 

acre  of  land  to  a  depth  of  one  foot.  As  the  area  of  an  acre 
is  43,560  square  feet,  the  acre  foot  is  equal  to  43,560  cubic 
feet,  or  a  stream  of  one  second  foot  would  have  to  flow  43,560 
seconds,  or  726  minutes,  or  12  hours  and  6  minutes  to  deliver 
one   acre   foot. 

How  Irrigation  Water  is  Measured. — There  are  two  prm- 
cipal  methods  of  measuring  irrigation  water.  1.  By  means  of 
the  current  meter,  and   (2),  by  means  of  "weirs." 

In  case  of  large  streams,  the  engineer  holds  a  current 
meter  for  a  certain  period  of  time  in  each  square  foot  of  an 
imaginary  cross  section  of  the  stream.  He  does  the  timing  by 
means  of  a  stop  watch.  Now,  when  he  has  the  number  of 
revolutions  per  second  or  per  minute,  he  consults  a  table 
which  accompanies  the  meter,,  and  thus  computes  the  number 
of  feet  of  flow  per  second  of  that  given  foot  of  cross  section. 
When  he  has  measured  all  the  square  feet,  he  adds  the  total 
number  of  second  feet  and  thus  gets  the  number  of  second 
feet   in   the   stream. 

One  must  measure  each  square  foot  because  there  are 
different  rates  of  flow  in  different  parts  of  the  stream.  Gen- 
erally speaking,  the  water  flows  more  rapidly  in  the  center, 
than  at  the  sides,  and  it  flows  more  rapidly  near  the  surface 
than  near  the  bottom.     The  rough  banks  retard  the  flow. 

Special  "flumes"  are  sometimes  built  and  each  inch  or 
tenth  foot  of  depth  is  computed  with  a  meter.  These  flumes 
are  called  "rating  flumes."  The  ditch  rider  can  tell  at  a  glance 
at  the  gauge  rod,  how  many  cubic  feet  per  second  are  passing 
through  the   rating   flume. 

The  "Weir." — By  bringing  water  to  a  standstill,  and  then 
allowing  it  to  pour  over  a  clean  cut  notch  in  the  side  of  the 
pool,  we  are  able  to  compute  accurately,  just  how  many  cubic 
feet  per  second  go  over  the  notch.  Several  forms  of  weirs 
are  used,  but  the  cippoletti  weir  is  the  most  practical.  The 
notch  is  cut  in  the  weir  board,  so  that  the  bottom  of  the 
notch  ("the  crest")  is  at  least  twice  as  high  from  the  bottom 
of  the  box  as  the  depth  of  water  which  will  flow  over  the 
crest.  The  ends  of  the  crest  should  be  twice  as  far  from  the 
sides  of  the  box  as  the  depth  of  water  over  the  crest. 


62 


FARM  ENGINEERhNG 


The  sides  of  the  notch  slope  outward  at  the  rate  of  1 
inch  on  each  side  to  4  inches  in  height,  (1  to  4).  The  edges 
of  the  notch  are  sharp  and  the  bevel  of  the  edge  is  on  the 
down  stream  side  of  the  board.  The  board  may  be  set  in  a 
weir  box,  (see  Plate  27),  or  in  the  straight  run  of  a  turnout 
box.  (see  Plate  28).  The  board  may  also  be  set  in  a  con- 
crete cross  wall  which  dams  up  the  current  of  a  stream  and 
forms  a  little  lake.  The  board  should  be  at  right  angles  to 
the  stream,  and  the  stream  should  jump  over  the  notch  and 
drop  clear  of  everything  into  the  stream  below.  It  should 
"jump  over  air."  The  water  as  it  comes  to  the  pond  or  box 
should  be  brought  to  a  standstill  and  allowed  to  pass  over  the 


Plate  26.  Plate  20  is  a  photo  of  three  current  meters.  Fig.  A  is  »n 
Acoustic  Meter  such  as  the  engineer  is  using  in  Plate  25.  Fig.  B 
is  a  current  meter  which  is  fitted  with  an  electric  sounder  which 
gives  a  buzz  at  each  recording  stroke.  (See  Gurley's  manual  for 
description  and  for  the  reduction  tables  for  use  with  these  meters.) 
Fig.  C  is  a  very  small,  yet  accurate,  current  meter.  It  is  for  us« 
in  small  streams  and  ditches.  It  is  not  supplied  with  "staff."  It 
has  electric  recording  device.  (See  Keuffel  &  Esser  Catalogue  for 
detailed  information.)  This  is  a  collection  of  strictly  high  grad« 
current  meters.) 


FARM  ENGINEERING 63 

weir  as  from  a  large,  quiet  lake.  This  abolishes  "speed  of  ap- 
proach'' and  makes  the   weir  a  very   accurate  water  meter. 

The  height  of  the  water  on  the  crest  is  measured  not  di- 
rectly over  the  crest,  but  back  in  the  box  at  least  6  feet  from 
the  weir.  A  stake  is  driven  until  its  top  is  exactly  level  with 
the  crest.  The  rod  is  placed  on  the  stake,  and  the  depth  of 
the  water  above  the  top  of  the  stake  is  the  depth  over  the 
crest.  This  is  done  to  do  away  with  the  "sink"  of  the  water 
as  it  comes  to  the  crest.  Don't  forget  to  measure  back  from 
the  weir  at  least  six  feet,     (see  Plate  29). 

The  following  table,  tells  how  much  water  flows  over 
weirs  from  1  foot  wide,  to  10  feet  wide  for  each  1/100  foot  in 
depth.     The  unit  is  cubic  foot  per  second. 


Plate  27.  A  weir  box  made  of  planks  and  timbers.  The  weir  is  of  the 
type  known  as  the  Cippoletti  weir.  Notice  that  the  sides  of  the 
notch  slant  out  at  the  rate  of  one  inch  on  each  side  to  four  inches  in 
height  of  the  notch.  The  arrow  shows  which  way  the  current  passes 
through   the   box. 


64 


FARM  ENGINEERING 


The  following  table  is  taken  from   Bulletin  72  of  Montana 
Experiment   Station :      (This   bulletin   is   now  out  of  print.) 


i    1 

1.4 

4 

j-1 

^ 

u 

t-t 

t^ 

u, 

t^ 

^ 

.J 

o  « 

» 

f 

1 

% 

1 

"5 

% 

^ 

^  s 

_^ 

o 
o 

*^ 

^ 

4J 

^_^ 

^ 

4^ 

^ 

+o 

o 

.  +3  O 

o 

o 

o 

o 

O 

o 

o 

o 

o 

c 

ft  , 

o 

1 

o 

o 

o 

O 

o 

o 

o 

o 

SB 

i^ 

*f-i 

•M 

•w 

%^ 

tH 

C" 

-^ 

IN 

s 

■^ 

la 

O 

J>- 

ob 

a, 

Cu.  tfi 

tiu.ft. 

Cu.  It.  Cu.  ft. 

Cu.ft.lCu.  ft. 

Cu.  ft. 

Cu.ft.lCu.  ft. 

Cu.  ft. 

Cu.  ft. 

reet 

p'raec 

p'r  gee 

p'r  sec  p'r  secip'r  sec  p'r  sec 

p'r  sec  p'r  sec  p'r  sec 

p'r  sec 

p'r  sec 

e.oi 

0.0034 

O.0O51 

0.0067 

0.0101 

0.0135 

0.0168 

0.02021  0.0236  0.0269 

0.0303 

0.0337 

M 

.0095 

.0143 

.0190 

.0286 

.0381 

.0476 

.0571 

.0667   .0762 

.0857 

.03.52 

.9S 

.0175 

.0262 

.0350 

.0.525 

.0700 

.0875 

.10-30 

.1225   .1400 

.1574 

.1749 

.04 

.0269 

.0404 

.0539 

.0808 

.1077 

.1347 

.1616 

.1885 

.2155 

.2424 

.2693 

.05 

.0676 

.0565 

.0753 

.1129 

.1506 

.1882 

.2258 

.2635 

.3011 

.3388 

.3764 

.06 

.0495 

.0742 

.0990 

.1484 

.1979 

.2474 

.2969 

.3464 

.3958 

.4453 

.4948 

.07 

.0624 

.0935 

.1247 

.1871 

.2494 

.3118 

.3741 

.4365 

.4988 

.5612 

.6235 

.08 

.0762 

.1143 

.1524 

.2285 

.8047 

.3809 

.4571 

.5333'  .6095 

.6856 

.7618 

.08 

.0909 

.1364 

.1818 

.2727 

.3636 

.4545 

.5454 

.63631  .7272 

.8181 

.9090 

.10 

.1065 

.1597 

.2129 

.3194 

.4259 

.5323 

.6388 

.7452;  .8517 

.9582 

1.0646 

.11 

.1228 

.1842 

.2457 

.3685 

.4913 

.6141 

.7370 

.8598!  .9826 

1.10-34 

1.2283 

.12 

.1399 

.2099 

.2799 

.4198 

.5598 

.6997 

.8397 

.9796!  1,1196 

1.2595 

1.3995 

.18 

.1578 

.2367 

.3156 

.4734 

.6312 

.7890 

.9468 

1.1046,  1.2624 

1.4202 

1.5780 

.14 

.1764 

.2645 

.3527 

.5291 

.7034 

-.8818 

1.0581 

1.2455  1.4106 

1..5872 

1.7336 

.15 

.1956 

.2934 

.3912 

.5868 

.7823 

.9779 

1.1735 

1.3691'  1.5647 

1.7603 

1.9559 

.16 

.2155 

.3232 

.4309 

.6464 

.8619 

1.0773 

1.2928 

1.5083;  1.7237 

1.9392 

2.1547 

.17 

.2360 

.3540 

.4720 

.7079 

.9439 

1.1799 

1.4159 

1.65191  1.8878 

2.1238 

2.3598 

.18 

.2571 

.3857 

.5142 

.7713 

1.0284 

1.2855 

1.5426 

1.79971  2.0568 

2.3139 

2.. 5710 

.19 

.2788 

.4182 

.5576 

.8365 

1.1153 

1.3942 

1.6729 

1.9518 

2.2306 

2.5094 

2.7882 

.20 

.3011 

.4517 

.6022 

.9034 

1.2045 

1.5056 

1.8068 

2.1079 

2.4090 

2.7101 

3.0112 

.21 

.3240 

.4860 

.6480 

.9720 

1.2960 

1.6199 

1.9439 

2.2679 

2.5919 

2.91-"9 

3.2.S99 

.22 

.3474 

.5211 

.6948 

1.0422 

1.3896 

1.7370 

2.0844 

2.4318 

2.7792 

3.1266 

3.4740 

.23 

.8714 

.5570 

.7427 

1.1141 

1.4854 

1.8568 

2.2281 

2.5995 

2.9709 

3.3422 

3.7136 

.24 

.3958 

.5938 

.7917 

1.1875 

1.5834 

1.9792 

2.3750 

2.7709 

3.1667 

3.5625 

3.9584 

.25 

.4208 

.6312 

.8417 

1.2625 

1.6833 

2.1042 

2.5250 

2.9458 

3.3666 

3.7875 

4.2083 

.26 

.4463 

.6995 

.8927 

1.3390 

1.7853 

2.2317 

2.6780 

3.1243 

3.5707 

4.0170 

4.4633 

.27 

.4723 

.7085 

.9447 

1.4170 

1.8893 

2.3617 

2.8'130 

3.3063 

3.7787 

4.2510 

4.7233 

.28 

.4988 

.7482 

.9976 

1.4964 

1.9952 

2.4941 

2.9929 

3.4917 

3.9905 

4.4893 

4.9881 

.29 

.5258 

.7887 

1.0515 

1.5773 

2.1031 

2.6289 

3.1546 

3.6804 

4.2062 

4.7319 

5.2577 

.30 

.5532 

.8298 

1.1064 

1.6596 

2.2128 

2.7660 

3.3192 

3.8724 

4.4256 

4.9788 

5.5320 

.31 

.5811 

.8716 

1.1622 

1.7433 

2.3244 

2.9054 

3.4865 

4.0676 

4.6487 

5.2298 

5.8109 

.K2 

.6094 

.9141 

1.2189 

1.8283 

2.4377 

3.0472 

3.6.566 

4.2660 

4.87.54 

5.4849 

6.0943 

33 

.6382 

.9573 

1.2764 

1.9147 

2.5529 

3.1911 

3.8293 

4.4675 

5.1058 

5.7440 

6.3822 

.34 

.6674 

1.0012 

1.3S49 

2.0023 

2.6698 

3.3372 

4.0047 

4.6721 

5.3396 

6.0070 

6.6745 

.35 

.6971 

1.0457 

1.3942 

2.0913 

2.7884 

3.4556 

4.1827 

4.8798 

5.5769 

6.2740 

6.9711 

.36 

.7272 

1.0908 

1.4544 

2.1816 

2.9088 

3.6360 

4.3632 

5.0904 

5.8175 

6.5448 

7.2720 

.87 

.7577 

1.1366 

1.5154 

2.2731 

3.0308 

3.7885 

4.4563 

5.3040 

6.0617 

6.8194 

7.5771 

.88 

.7886 

1.1830 

1.5773 

2.3659 

3.1545 

3.9432 

4.7318 

5.5204 

6.3091 

7.0977 

7.8863 

.39 

.8200 

1.2300 

1.6399 

2.4599 

3.2799 

4.0998 

4.9198 

5.7398 

6.5597 

7.3797 

8.1997 

.40 

.8517 

1.2776 

1.7034 

2.5551 

3.4068 

4.2585 

5.1102 

5.9619 

6.8137 

7.6654 

8.5171 

.41 

.8838 

1.8258 

1.7677 

2.6515 

3.5354 

4.4191 

5.3031 

6.1869 

7.0708 

7.9546 

8.8384 

.42 

.9164 

1.3746 

1.8328 

2.7491 

3.6655 

4.5819 

5.4983 

6.4146 

7.3310 

8.2474 

9.1638 

.43 

.9493 

1.4239 

1.8968 

2.8479 

3.7972 

4.7465 

5.6958 

6.6451 

7.5944 

8.5437 

9.4930 

.44 

.9826 

1.4739 

1.9652 

2.9478 

3.9304 

4.9130 

5.8956 

6.8782 

7.8608 

8.8434 

9.8261 

.45 

1.0163 

1.5244 

2.0326 

3.0489 

4.0652 

5.0815 

6.0978 

7.1141 

8.1303 

9.1466 

10.1629 

.46 

1.0504 

1.5755 

2.1007 

3.1511 

4.2014 

5.2518 

6.3021 

7.3525 

8.4029 

9.4532 

10.5036 

.47 

1.0848 

1.6272 

2.1696 

3.2544 

4.3392 

5.4240 

6.5088 

7.5936;  8.6783 

9.7631 

10.8479 

.48 

1.1196 

1.6794 

2.2392 

3.3588 

4.4784 

5.5980 

6.7178 

7.8372'  8.9567 

10.0764 

11.196« 

.49 

1.1548 

1.7321 

2.3095 

3.4643 

4.6191 

5.7738 

6.9286 

8.0834 

9.2381 

10.3929 

11.547T 

.GO 

I.190e 

1.7854 

2.3806 

3.5709 

4.7612 

5.9515 

7.1418 

8.3321 

9.5224 

10.7127 

11.9030 

M 

1.8393 

2.4524 

3.6785 

4.9047 

6.1309 

7.3571 

8.5833 

9.8095 

11.0336 

12.2618 

.B3 



1.8936 

2.5248 

3.7873 

5.0497 

6.3121 

7.5745 

8.8370 

10.0994 

11.3618 

12.6242 

.U 

1.9485 

2.5980 

3.8970 

5.1961 

6.4951 

7.7941 

9.0931 

10.3921 

11.6911 

12.9901 

.54 

2.0039 

2.6719 

4.0079 

5.3438 

6.6798 

8.0157 

9.8517 

10.6876 

12.0236 

13  3595 

M 

2.0598 

2.7465 

4.1197 

5.4929 

6.8662 

8.2394 

9.6126 

10.9859 

12.3591 

13.7328 

.U 

X.1163 

2.8217 

4.2326 

5.6434 

7.0543 

8.4651 

9.8760ill.2868 

12.6977 

14.1085 

.67 

♦.1732 

2.8976 

4.8464 

5.7953 

7.2441 

8.6929 

10.1417 11.5905 

13.0393 

14.4881 

.58 

2.2807 

2.S742 

4.4613 

5.9484 

7.4355 

8.9226 

10.4097  11.8969 

13.8840 

14.87U 

M 

J.2888 

8.0515 

4.5772 

8.1029 

7.6287 

9.1544 

10.6801112.2059 

13.7613 

15.2578 

.to 

2.8470 

8.1294 

4.6940 

6.2587 

7.8234 

9.3881 

10.952712.5174 

14.0821 

15.6468 

FARM  ENGINEERING 

65 

a    1 

o  " 

Is 

O 

o 

"53 

o 
o 

0 

0 
0 

CO 

1 

0 

0 
0 

% 
§ 

CO 

% 

0 
0 

0 
0 

00 

% 

c 
0 

en 

1 

0 

-0 

Jr^Ct 

Cu.ft. 
p'riM 

Cu.lt.lCu.ft.lCu.lt.lCu.lt. 
p'r  gecip'r  sec  p'r  lec  p'r  gee 

Cu.  ft. 
p'r  »ec 

Cu.lt.jCu.  ft. 
p'r  secp'r  see 

Cu.  ft. 
p'r  gee 

Cu.  It. 
p'r  sec 

Cu.  tt. 

p'r  ge« 

.61 
62 
.63 
.64 
.65 
M 
.67 
.68 
.00 
.70 
.71 
.72 
.73 
.74 
,  .75 
.76 
.77 
.78 
.79 
.80 
.81 
.82 
.89 
.84 
.85 
.86 
.87 
.88 
.88 
.90 
.91 
.92 
.93 
.94 
.95 
.96 
.97 
.98 
.99 
1.00 
1.01 
1  02 



2.4059 
2.4654 
2.5252 
2'.  5856 
2.64S4 
2.7077 
2.7695 
2.8317 
2.8944 
2.9576 
8.0212 
3.0852 
3.1497 
3.2147 
S.2801 

3.2079 
S.2871 
3.3670 
3.4475 
3.5286 
3.6103 
3.6927 
3.77.57 
3.8593 
3.9435 
4.0283 
4.1137 
4.1997 
4.2863 
4.3734 
4.4612 
4.5495 
4.6384 
4.7279 
4.8180 
4.9086 
4.9998 
5.0915 
5.1838 
5.2767 
5.3700 
5.4640 
5.5585 
5.6535 
5.7490 
5.8451 
5.9417 
6.0389 
6.1365 
6.2347 
6.3334 
6.4326 
6.5323 
6.6326 
«.7330 

4.8119 

4,9307 
5,0505 
5,1712 
5,2929 
5,4155 
5,5380 
5,6635 
5.7889 
5.9152 
6.0424 
6.1705 
6.2995 
6.4294 
6.5601 
6.6918 
6.8243 
6.9577 
7.0919 
7.2270 
7.3629 
7.4997 
7.6373 
7.7757 
7.9150 
8.0551 
8.1960 
8.3377 
8.4802 
8.6235 
8.7677 
8.9126 
9.0583 
9.2048 
9.3520 
9.5001 
9.6489 
9.7985 
9.9489 
10.1000 

6.4159 

6.5743 

6.7340 

6.8949 

7.0572 

7.2206 

7.3854 

7.5513 

7.7185 

7.8869 

8.0565 

8.2273 

8.3993 

8.5725 

8.7469 

8.9224 

9.0991 

9.2769 

9.4559 

9.6360 

9.8172 

9.9996 

10.1830 

10.3676 

10.5.533 

10.7401 

10.9280 

11.1169 

11.3069 

11.4980 

11.6902 

11.8834 

12.0777 

12.2730 

12.4694 

12.6668 

12.86(12 

13.0647 

13.2652 

13.4667 

8.0198 

8.2178 

8.4175 

8.6187 

8.8215 

9,0258 

9.2317 

9.4392 

9.6481 

9,8586 

10.0706 

10.2842 

10.4992 

10.7156 

10.9336 

11.1530 

11.3728 

11.5961 

11.8198 

12.0450 

12.2715 

12.4995 

12.7288 

12.9595 

13.1916 

13.4251 

13.6599 

13.8961 

14.1337 

14.3726 

14.6128 

14.8543 

15.0971 

15.3414 

15.5867 

15.8335 

16.0815 

16.3309 

16.5815 

16.8333 

9.6238 
9.8614 
10.1009 
10.3424 
10.5857 
10.8310 
11.0781 
11.3270 
11.5778 
11.8304 
12,0848 
12.3410 
12..599n 
12.8588 
13.1203 
13.3836 
13.6486 
13.9153 
14.1838 
14.4539 
14.7258 
14.9993 
15.2746 
15..5514 
15.8300 
16.1101 
16.3919 
16.6754 
16.9604 
17.2470 
17.5353 
17.8251 
18.1166 
18.4096 
18.7041 
19.0002 
19.2979 
19.5970 
19.8978 
20.2000 
20.5038 
20.8090 
21.1158 
21.4240 
21.7338 
22.0450 
22.3577 
22,6719 
22.9875 
23.3045 
23.6230 
23.9430 
24.2644 
24.5872 
24.9114 
25.2370 
25.5641 
25.8925 
26.2224 
26.5536 

11.2278 
11.5050 
11.7844 
12.0ti61 
12.3500 
12.6361 
12.9244 
13.2148 
13,5074 
13.8021 
14,0989 
14.3978 
14.6988 
15.0019 
15..3070 
15.6142 
15.9233 
16.2345 
16.5477 
16.8629 
17.1801 
17.4992 
17.8202 
18.1433 
18.4683 
18.7952 
19.1239 
19.4546 
19.7872 
20.1216 
20.4579 
20.7960 
21.1360 
21.4778 
21,8214 
22.1669 
22.5142 
22.8632 
23,2141 
23.5667 
23.9211 
24.2772 
24.6351 
24.9947 
25.3561 
25.7192 
26.0840 
26.4505 

12  8317 
13,1486 
13,4679 
13,7899 
14,1143 
14  4413 
14,7707 
15,1027 
15.4370 
15.7738 
16.1130 
16.4547 
16.7989 
17.1450 
17.4937 
17.8447 
18.1981 
18.5538 
18.9117 
19.2719 
19.6344 
19.9991 
20.3661 
20.7352 
21.1066 
21.4802 
21.8559 
22.2338 
22.6139 
22.9661 
23.3804 
23.7669 
24.1554 
24.5461 
24.9388 
25.3336 
25.7305 
26.1294 
26.5303 
26.9333 
27.3384 
27.7454 

14.4357 

14.7921 
15.1514 
15.5136 
15.8786 
16.2465 
16.6171 
16.9905 
17.3667 
17.7456 
18,1272 
18.5115 

18  898" 

19  2S81 
19.6804 
20.0753 
20.4729 
20.8730 
21.2757 
21  6809 
22.0887 
22.4990 
22.9118 
23.3271 
23.7449 
24.1652 
24.5879 
25.0131 
25.4406 
25,8706 
26.3030 
26.7377 
27.1748 
27,6143 
28,0561 
28.5003 
28.9468 
29.3956 
29.8467 
30.3000 
30.7556 
31.2135 

16.0396 

16.4357 

16.8349 

17.237S 

17.6429 

18.0516 

18.4634 

18.8783 

19.2963 

19.7173 

20.1413 

20.5683 

20.9983 

21.4313 

21.8671 

22.3059 

22.7476 

23.1922 

23,6396 

24.0899 

24.54.30 

24.9989 

25.4576 

25.9191 

26.383.'? 

26.8502  ■ 

27.3199 

27.7923 

28.2574 

28.7451 

29.2255 

29.7086 

30.1943 

30.6826 

31.1735 

31.6670 

32.1631 

32.6617 

33.1629 

33.6667 

34.1729 

34.6817 

1.03 
1.04 
1  05 







28.1544  31.6737,35.1930 
28.5654  32.1361135.7067 
28.9784|32.fi0O7  36.23.'JO 

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1.07 
1  06 







29.3933  33.0675  36.7417 
29.8103 '33, 5365  37.2628 
30.229l'34.0O78'37.7864 

109 
1 10 









26.8187 
27  1886 

30.6499  34.4812, 38.3124 
31.0727  34,9568  38,8409 

1.11 

27.5602 
27.9335 
28.3084 
28.6850 
29.0633 
29.4432 
29.8248 
30.2079 
30.5928 
30.9792 
31.3672 
31.7569 
32.1481 

31.4974|35.4346:30.3717 

1.12 
1.13 







31.9240  35.914539.9050 
32  3525i36.3965  40.4406 

1  14 

32.7829  36.8808  40.9786 

1 15 

33.2152 j37. 3671  41.5190 

I.IC 

1.17 

,  1.18 

1.19 









33.6494137.8556 
34.0854^38.3461 
34.5234138.8388 
34.963139,3335 

42.0617 
42.6068 
43.1542 
43.7039 

1.20 
1.21 
122 











35.4048 

35.8483 
36.2936 
36.7407 

39.8304 
40.3393 
40.8303 
41.3333 

44.2560 
44.8103 
45.3670 

1  23 

45.92.'io 

66 FARM  ENGINEERING 

In  case  the  engineer  wishes  to  measure  the  depth  in 
inches  rather  than  in  hundredths,  he  may  consult  the  follow- 
ing table.  He  can  find  the  number  of  miner's  inches  which 
will  pass  over  the  weirs.  Each  miner's  inch  in  this  particular 
table  is  equal  to  1/40  of  a  cubic  foot  per  second.  So,  by  divid- 
ing the  number  of  miner's  inches  by  40,  we  get  the  number 
of  cubic   feet  per  second. 

The  following  table  is  taken  from  Bulletin  72  of  Montana 
Experiment  Station :  (The  supply  of  this  bulletin  has  been 
exhausted.) 


Plate  128.  A  concrete  luru-uut  hux.  The  ditch  brhigs  the  water  in  at  the 
right.  It  may  flow  straight  through,  or  by  putting  tightly  fitting 
boards  in  the  slots  of  the  main  channel  the  water  can  be  turned  to 
right  and  left.  Then  by  putting  boards  in  the  left  wing  the  w^ater 
can  be  turned  to  the  right.  If  boards  be  placed  in  the  left  slots 
then  the  water  runs  into  the  right  (closed)  wing.  In  this  case 
the  water  is  delivered  into  a  tile  which  enters  the  bottom  of  the 
right  wing.  If  the  side  slots  be  closed  to  the  top  and  a  low  board 
with  a  weir  slot  in  its  upper  edge  be  inserted  in  the  main  channel 
of  the  box,  then  the  turn-ot  box  is  convuerted  into  a  weir  box.  Tht 
gauge  peg  should  be  located  at  least  six  feet  upstream  from  the  weir, 
Its  top  should  be  level  with  the  crest  of  the  weir. 


FARM  ENGINEERING 

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97 

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191 

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173 

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178 

207 

237 

267 

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93 

124 

155 

185 

216 

247 

278 

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4% 

32 

48 

64 

97 

129 

161 

193 

226 

258 

290 

322 

4% 

34 

50 

67 

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167 

201 

235 

268 

302 

335 

4y8 

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70 

105 

139 

174 

209 

244 

279 

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5 

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326 

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150 

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263 

301 

338 

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156 

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273 

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282 

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42 

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251 

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138 

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231 

277 

323 

369 

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286 

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381 

429 

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98 

147 

196 

246 

295 

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393 

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51 

76 

101 

152 

202 

253 

304 

354 

405 

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156 

209 

261 

313 

365 

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107 

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215 

269 

322 

375 

429 

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110 

166 

221 

276 

331 

387 

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497 

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227 

284 

341 

398 

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568 

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58 

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117 

175 

234 

292 

350 

409 

467 

525 

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7 

60 

90 

120 

180 

240 

300 

360 

420 

480 

540 

600 

71/8 

62 

92 

123 

185 

246 

308 

370 

431 

493 

554 

616 

7% 

63 

95 

126 

190 

253 

316 

379 

443 

506 

569 

632 

7% 

65 

97 

130 

195 

260 

324 

389 

454 

519 

584 

649 

7% 

67 

100 

133 

200 

266 

333 

399 

466 

532 

599 

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7% 

68 

102 

136 

205 

273 

341 

409 

477 

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70 

105 

140 

210 

280 

349 

419 

489 

559 

629 

699 

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72 

107 

143 

215 

286 

358 

430 

501 

573 

644 

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8 

73 

110 

147 

220 

293 

367 

440 

513 

586 

660 

733 

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75 

113 

150 

225 

300 

375 

450 

525 

600 

675 

750 

81/4 

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115 

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307 

384 

461 

537 

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768 

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79 

118 

157 

236 

314 

393 

471 

550 

628 

707 

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80 

120 

161 

241 

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401 

482 

562 

642 

722 

803 

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82 

123 

164 

246 

328 

410 

492 

574 

656 

739 

821 

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84 

126 

168 

252 

335 

419 

503 

587 

671 

755 

838 

8% 

86 

128 

171 

257 

343 

428 

514 

599 

685 

771 

856 

ft 

87 

131 

175 

262 

350 

437 

525 

612 

700 

788 

875 

91/8 

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134 

179 

268 

357 

446 

536 

625 

714 

804 

893 

91/4 



137 

182 

273 

364 

456 

547 

638 

729 

820 

911 

9% 

._ 

139 

186 

279 

372 

465 

558 

651 

744 

837 

930 

9% 

142 

190 

285 

379 

474 

569 

664 

759 

851 

949 

9% 

.. 

1^5 

193 

290 

387 

484 

580 

677 

774 

861 

967 

93/4 

.. 

148 

197 

296 

394 

493 

592 

690 

789 

888 

986 

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. 

151 

201 

302 

402 

503 

603 

704 

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154 

205 

307 

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612 

615 

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522 

626 

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159 

213 

319 

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532 

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162 

217 

325 

433 

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220 

331 

441 

551 

661 

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355 

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591 

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481 

601 

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FARM  ENGINEERING 


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Inches 


ri-/8 

12 

1?% 

1.214 

12% 

n% 
■12% 
13 
131/3 
131/4 
133/^ 
131/2 
^3% 

13% 

13% 

14 

1^% 

141/4 

14% 

141/3 

14% 

143/4 

11% 

15 

15% 

151/4 

15% 

15% 

15% 

153/4 

15% 

16 

16% 

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lfi% 

lfi% 

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16% 

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17% 

171/4 

17% 

17% 

17% 

173/4 

17% 

18 


Min-  !  Min-     Min- 
ers'      erg'       era' 
inches  inches  Inches 


265 
269 


Min- 
ers' 
Inches 


398 
404 
410 
417 
423 
430 
436 
442 
449 
456 
462 
469 
475 


Min- 
ers' 
Inches 


430 

539 

547 

556 

564 

573 

582 

590 

599 

607 

616 

625 

634 

6^3 

652 

661 

670 

679 

688 

697 

706 

715 

725 

734 

743 

753 


Min-  j  Min- 
ers'      ers' 
inches  inches 


663 
673 

68- 

694 

705 

716 

726 

737 

748 

759 

770 

781 

792 

803 

815 

826 

837 

8v9 

860 

871 

883 

894 

906 

918 

929 

941 

953 

965 

977 

989 

1001 

1013 

1025 

1037 

1049 

1061 

1073 

1086 

1098; 

1110 

1123 

1135 


795 
808 
821 
833 
846 
859 
872 
885 
898 
911 
924 
938 
951 
964 
978 
991 
1005 
1019 
1032 
1046 
1059 
1073 
1087 
1101 
1115 
1129 
1143 
1158 
1172 
1186 
1201 
1215 
1229 
1244 
1259 
1273 
1288 
1303 
1318 
1333 
1348 
1363 
1378 
1393 
1408 
1423 
1438 
l'^54 
1469 
1484 


Min- 
ers' 
inches 


928 
943 
958 
972 
987 
1002 
1017 
1032 
1048 
1063 
10781 
109-' 
1109 
1125 
1140 
1156 
1172 
1189 
120' 
1220 
1236 
1252 
1268 
1285 
13011 
13171 
133-'; 
1351 
1368 
1385 
1402 
1419 
1437 
1455 
1472 
1^89 
1506 
15^3 
1539 
15561 
15721 
1589 
1607! 
1625! 
1642| 
1660' 
1678j 
1696i 
17141 
I732I 


Min- 
ers' 
inches 


1060 
1077 
1094 

nil 

1128 
1145 
1162 
1180 
1197 
1215 
1232 
1250 
1268 
1286 
1303 
1321 
13-^0 
1359 


Min- 
ers' 
inches 


1193 
1212 
1231 
1260 
1269 
1289 
1308 
1328 
1348 
1368 
1389 
1.09 
1429 
1449 
1469 
1489 
1509 
1530 
13761  1550 
13941  1570 
1412 i  15901 
143li  1610! 
14491  163] I 
1--68'  1652! 

1487:    1673: 

1506  1694: 
1524!  1715! 
15431  1736: 
1562!  1757 
1580    1778 


Min- 
ers' 
Inches 


1600 
lO'^O 
1639 
1659 
1678 
1698 
1717 
1737 


1801 
1822 
1844 
1866 


1910 
1932 
195^ 


1757  1976 
1777;  1999 
1797i  2021 
1817i  2044 
1837:  2066 
1857,!  2089 
1877!  2112 
1897!  213' 
1918  2157 
1938!  2181 
1959|  2204 
19791  2226 


1326 

1347 

1368 

1389 

1410 

1432 

1454 

1475 

1497 

1518 

1541 

1563 

1585 

1607 

1629 

1652 

1675 

1699 

1721 

1743 

1766 

1789 

1812 

1835 

1859 

1882 

1906 

1929 

1953 

1977 

2001 

2025 

2049 

2073 

2098 

2122 

2147 

2171 

2196 

2221 

2246 

2271 

2296 

2321 

234R 

2372 

2397 

2-^23 

2448 

2474 


70 FARM  ENGINEERING 

Ditches. — In  order  to  carry  irrigation  water  or  drainage 
water,  we  need  ditches.  The  laying  out  of  irrigation  ditches 
is  done  in  the  same  way  as  drainage  ditches,  except  that  we 
sometimes  use  dykes  to  carry  the  water  over  the  low  places. 
So  we  get  "Fill"  in  the  place  of  "Cut"  if  the  grade  happens 
to  have  a  greater  elevation  than  the  elevation  of  the  land. 


Plate  20.  Measuring  the  depth  of  the  ^Yatel■  over  a  weir.  The  rod  stands 
upon  a  solid  post,  the  top  of  which  is  exactly  the  same  height  as  the 
crest  ot  the  weir.  This  measurement  must  be  made  in  the  nearlj 
still  water  at  least  six  leet  back  from  the  weir.  (The  water  pitches 
down  as  it  approaches  the  weir.  There  are  .just  four-tenths  of  a  foot 
of  water  going  over  their  weir.) 

Sometimes  we  carry  water  past  Ioav  places  by  the  inverted 
siphon.  Some  "Practical  Drainage"  men  believe  they  can  use 
a  true  siphon  made  of  tile  drain  to  draw  water  over  a  hill. 
Their  drainage  projects  usually  fail  because  the  tile  are  not 
air  tight.     Tile  drains  should  be  run  "on  grade." 


FARM  ENGINEERING 


71 


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72       FARM  ENGINEERING 

Open  Ditches. — The  sides  of  the  open  ditches  usually 
slope  out  about  1  or  1^^  feet  on  each  side  to  each  foot  of 
depth.  The  banks  are  thus  kept  from  falling  in  and  clogging 
the  ditch.  In  general,  wide  ditches  are  preferable  because 
they   do  not   wash   so   deep,  or  change    courses   so   often. 

Drain  Tile.- — Drain  tile  are  of  three  general  classes :  square 
end  tile,  bevel  end  tile,  and  bell  end  tile.  They  may  be  classi- 
fied according  to  material  into  the  following  classes:  1.  Com- 
mon red  tile;  2.  Vitrified  or  glazed  tile;  and  3.  Cement  tile. 

The  common  red  tile  often  disintegrates  and  causes  trouble. 

The  glazed  tile  are  expensive  but  last  well. 

Dach'       ^'^ 


Plate  31.  In  Plate  31  is  shown  a  cross-section  of  a  railroad  track 
with  an  "inverted  siphon"  running  across  under  the  cut  and  the 
track.  The  ditch  comes  in  at  the  left,  (as  shown  by  arrow),  and 
the  water  runs  in  at  the  open  end  of  the  pipe  which  projects  through 
the  cement  cross-wall.  It  runs  under  the  track  and  the  force  of 
the  water  behind  drives  it  up  and  out  of  the  other  end  of  the  pipe, 
which  is  a  little  lower  than  the  in-take  end.  The  siphons  are  now 
being  built  as  large  as  eight  feet  in  diameter  and  several  miles  in 
length.  A  great  ditch  is  thus  carried  clear  across  the  "Bitter  Root 
Valley"  in  Montana. 

The  cement  tile  are  all  right  if  rightly  made,  and  laid 
where  no  alkalj  water  runs  through  them.  (See  Bulletin  81  of 
the  Montana  Experiment  Station.)  The  cement  tile  should 
be  of  a  rich  mixture  and  made  very  wet.  Otherwise  the  flow- 
ing water  will  soon  wear  holes  through  the  loose,  crumbly 
cement   sides. 

After  irrigation  water  has  been  measured  and  brought  to 
the    field   by   the    ditches,    it    is   turned   out    into    small    ditches 


FARM  ENGINEERING 


73 


by  means  of  turnout  boxes.  These  are  made  of  cement,  con- 
crete or  wood.  See  Plates  28  and  30.  In  case  of  deep  ditches, 
many  prefer  the  steel  head  gate.     See  Plate  21. 

The  methods  of  handling  the  water  on  the  land  vary  so 
much  that  it  is  impossible  to  go  into  detail  for  each  system. 
In  some  localities,  the  water  is  brought  into  tiles,  and  fed  to 
the  soil  from  below,  "sub-surface  irrigation."     In  some  locali- 


/7 


K-''— M- 


w 


J-/— j 


-|-~ 


J 


S 


Plate  32.  This  gives  an  idea  of  desirable  cross-sections  for  drainage  or 
irrigation  ditclies.  Figure  A  lias  a  slope  of  1  to  1.  That  is,  each 
side  slopes  out  one  foot  to  each  foot  of  depth.  Figure  B  is  of  a 
ditch  with  a  1  to  li4,  that  is,  each  side  slopes  out  one  foot  and  six 
inches  or  one  foot  and  five  tenths  to  each  foot  of  depth.  A  is 
satisfactory  for  ditches  through  hard  soil,  heavy  clay,  etc.,  while  B 
should  be  used  for  sandy  soil  or  any  easily  washed  soil. 

ties,  little  furrows  are  made,  two,  three  or  four  feet  apart,  and 
a  little  water  allowed  to  run  down  each  furrow.  This  is 
called  ''corrugated  irrigation."  Again,  in  some  parts  of  the 
country,  dykes  are  built  at  the  lower  sides. of  the  fields,  and 
the   water   is   allowed  to   flood   the   fields,   "flooding."     And   so 


74 


FARM  ENGINEERING 


we   find  all  of  these  systems  changed,   and   combined   until   we 
have  no  end  of  special  methods  of  irrigation. 

The    Preparation   of   Land   for   Irrigation, — It   is    necessary 

/7 


3 


8 


Plate  33.  This  shows  a  side  view  of  the  three  different  types  of  tile. 
Fig.  A  is  the  ordinary  "square-end"  tile.  Fig.  B  is  a  "bevel-.ioint" 
tile.  Fig.  C  is  a  "bell-end"  tile.  In  each  figure  the  side  of  the  tile 
has  been  cut  away  to  show  a  section  of  a  joint.  The  bel!-end 
tiles  are  usually  made  two,  three,  or  four  feet  long,  while  the  others 
are  usually  one  foot  long  in  small  sizes  and  two  feet  long  in  large 
sizes. 


Plate  34.  This  is  a  photo  of  the  latest  and  most  approved  tvpe  of  irri- 
gation leveler.  It  is  sixteen  feet  long  by  eight  in  width.  If  it  is 
to  be  used  on  light  soil  the  members  are  2"x(i"  ;  if  it  is  to  be  uped 
on  medium  soil,  2"xS'' ;  if  on  heavy  soil,  2"x]0"  or  even  2"xl2". 
The  braces  are  of  old  wagon  tire  and  the  chain  by  which  it  is  pulled 
is  a  log  chain.  From  two  to  six  horses  are  required  to  drag  it. 
It  rubs  off  the  high  spots  and  carries  the  soil  to  the  low  spots  and 
there  drops  it  automatically.  As  no  company  builds  these  useful 
machines,  the  farmer  builds  them  himself. 


FARM  ENGINEERING 75 

to  get  the  surface  of  the  field  free  from  little  high  spots  and 
low  spots,  before  irrigation  can  be  properly  done.  This  is 
accomplished  by  plowing  the  ground,  and  then  going  over  it 
with   an   irrigation   leveller. 

Control  of  Moisture,  and  Temperature  of  the  Soil  by  Means 
of  Scientific  Tillage. — If  wet  ground  is  rolled  with  a  heavy 
roller,  the  moisture  near  the  top  is  readily  evaporated  from 
the  surface.  The  evaporation  cools  the  soil,  just  as  the  evap- 
oration of  sweat  cools  the  human  body.  Thus  we  remove 
moisture  and  cool  the  soil  by  rolling. 

If  we  establish  a  surface  mulch  by  surface  tillage,  we  are 
able  to  prevent  evaporation,  and  thus  keep  the  soil  moisture 
from  evaporating.  This  also  brings  the  fine  particles  in  such 
a  position  that  they  can  absorb  heat  from  the  sun's  rays,  and 
as  they  are  not  cooled  by  rapid  evaporation,  the  soil  is  warmed. 

Thus  we  control  the  temperature  and  moisture  by  drain- 
age,  irrigation   and   scientific   tillage. 


TILE   LINES. 

The  general  use  of  drain  tile  both  for  the  purpose  of 
carrying  drainage  water  and  irrigation  water  as  well  as  sew- 
age makes  it  necessary  to  study  the  matter  carefully  before 
venturing  to  install  a  tile  system  of  carrying  water  or  sewage. 

Capacity  of  Tile  Drains. — No  attempt  is  made  here  to  go 
into  the  infinite  detail  of  the  carrying  capacity  of  drain  tile. 
It  is  well  for  the  student  to  know  that  the  capacity  of  a  tile; 

drain  or  conduit  varies  according  to  the  smoothness  of  the 
the  flow  also  depends  upon  the  depth  of  water  in  the  soil  above 
the  tile. 

The  following  table  gives  somewhere  near  the  flow  which 
we  might  expect  from  a  six-inch  tile  system  if  everything  was. 
in  good  working  order  and  the  work  of  laying  the  tile  had^ 
been    properly   done: 


16 


FARM  ENGINEERING 


Plate  35.  This  shows  three  systems  of  laying  out  tile  drains  or  open  drains. 
Fig.  A  is  the  branch  system.  The  main  line  goes  up  the  main  hollow 
or  low  ravine.  The  branches  may  extend  up  small  low  places  or 
they  may  be  extended  into  the  level  land  on  each  side  of  the  main 
ditch.  This  system  works  very  well  on  very  fiat  land  as  well.  Notice 
the  cross-wall  at  the  mouth  of  the  drain.  An  "upstream  wing"  pro- 
tects the  bank  from  washing  out.  Fig.  B  is  a*  side  branch  method 
which  resembles  a  gridiron.  In  case  one  wishes  to  drain  a  side  hill 
the  main  line  may  extend  along  the  base  of  the  hill  and  the  branches 
may  extend  up  the  side  of  t  le  hill.  Notice  that  the  tile  bends  down- 
stream in  each  case  before  the  branches  are  allowed  to  enter  the  main 
tile.  Also  notice  that  a  larger  tile  is  used  below  the  branches  than 
above.  If  the  grade  of  Fig.  B  were  reversed,  then  this  system  would 
be  suitable  for  the  discharge  of  sewage  water  from  a  water  tight 
cess-pool.  In  case  there  is  danger  of  the  outlets  (which  would  then 
be  at  the  ends  of  the  branches)  clogging  by  freezing,  the  water  should 
be  drawn  from  the  cess-pool  by  an  intermittent  siphon.  See  Farm 
Engineering,  Part  I  and  Iowa  Engineering  Experiment  Station  bulletin 
on  Sewage  Plants  for  Private  Houses.  Fig.  C  shows  a  combination 
of  systems  shown  in  A  and  B.  This  is  good  in  case  a  large  ravine 
has  many  smaller  side  ravines  which  are  separated  by  ridges  through 
which  it  is  impracticable  to  dig  the  ditches. 


FARM  ENGINEERING TL 

Inches  of  Number  of  second 

drop  per  feet  discharged 

hundred  ft.       •  from  tile. 

30  3/4 

24  5/8 

18  1/2 

12  3/8 

6  5/16 

3  1/4 

As  the  number  of  cubic  feet  of  discharge  will  vary  ap- 
proximately as  the  square  of  the  diameter  of  the  tile  one  might 
figure  the  capacity  of  the  different  sizes  of  tile  from  the  above 
table.  To  get  the  discharge  of  a  three-inch  tile.  6X6=36. 
3x3=9.  36^9=4.  Then  a  three-inch  tile  will  carry  approxi- 
mately   Yx    ^s   much    as   a   six-inch   tile. 

To  find  the  capacity  of  a  twelve-inch  tile.  6X6=36. 
12X12=144.  144  is  four  times  as  great  as  36  so  we  might  ex- 
pect four  times  as  much  discharge  from  the  larger  pipe.  This 
is  based  on  the  fact  that  the  area  of  a  circle  increases  as  the 
square    of   the   diameter. 

As  there  is  more  resistance  per  unit  of  area  of  cross  sec- 
tion in  the  small  tile  the  increase  in  discharge  will  be  greater 
in  proportion  to  the  cross  section  in  large  tile  than  it  will  be 
in  small  tile. 

Systems  of  Laying  Tile. — There  are  a  great  many  systems 
of  laying  out  tile  drains.  The  student  must  apply  some  one 
of  these  systems  and  make  such  combinations  as  he  sees  fit. 


TILE    DRAINAGE. 

In  different  parts  of  the  country  the  people  hold  widely 
different  opinions  in  regard  to  the  proper  methods  of  draining 
land.  In  general  it  may  be  said  that  they  do  not  really  under- 
stand  the   advantages   to  be   derived  from   drainage. 

Many   believe   that   when    they    have   removed    the   surface 


78 FARM  ENGINEERING ^_ 

water  they  have  properly  drained  the  field.  In  a  large  ma- 
jority of  cases  the  idea  is  absolutely  wrong.  Again  we  often 
meet  those  who  really  believe  that  all  the  water  should  re- 
main on  the  land  in  order  to  produce  a  crop.  Such  people 
have  little  or  no  idea  of  the  detrimental  effects  which  result 
from  a  "high  water  table."  By  a  high  water  table  we  mean 
the  height  of  the  free  water  in  the  soil. 

The  student  should  understand  that  there  are  three  types 
of  water  in  the   soil : 

1st — Free  water,  that  type  of  water  which  may  flow  from 
place  to  place.  Such  water  flows  into  a  well  or  cellar  which 
penetrates  below  the  water   table. 

2nd — Capillary  water.  This  type  of  water  is  in  the  form 
of  a  thin  film  which  covers  the  surface  of  each  particle  of 
moist   soil. 

3rd — Hygroscopic  moisture.  This  form  cannot  be  seen 
but  when  soil  which  is  apparently  very  dry  is  heated,  it  loses 
weight.    This  is  due  to  the  loss  of  water  which  we  cannot  see. 

In  all  three  cases  the  water  is  of  the  same  composition, 
but  its  effects  on  plant  growth  are  very  different.  Both  hy- 
groscopic and  capillary  moisture  promote  plant  growth,  while 
the  free  moisture  causes  the  plants  to  actually  drown.  Of 
course  many  aquatic  plants  can  live  with  their  roots  in  free 
water,  but  we  must  remember  that  such  plants  as  corn,  oats, 
wheat,  barley,  rye,  clover,  timothy,  alfalfa,  etc.,  are  not  aquatic. 
The  roots  reach  into  the  soil  for  plant  food  and  moisture,  but 
when  they  reach  a  very  high  water  table  they  often  perish. 

In  the  light  of  the  above  facts,  it  is  easy  to  understand 
why  subsurface  or  "under  drainage"  often  causes  land,  which 
has  previously  been  unproductive,  to  produce  abundant  crops. 

The  author  has  never  met  with  a  case  where  a  thorough 
system  of  under  drainage  really  caused  the  land  to  "dry  out" 
as  some  people  imagine  it  would. 

As  a  matter  of  fact,  neither  capillary  or  hygroscopic  mois- 
ture  can   be   drawn   from   the   land   by   an   underground   drain. 


FARM  ENGINEERING  79 


It  is  only  the  free  water  that  is  really  affected. 
Systems  of  underdraining : 


Mole  Ditches. 

Some  years  ago  a  machine  was  devised  which  forced  a 
bullet  shaped  piece  of  iron  through  the  soil,  at  a  depth  of 
from  one  to  three  feet.  The  ditch  worked  much  as  a  modern 
tile  drain  works,  but  it  soon  caved  in  on  nearly  level  land, 
while  in  hilly  land  the  water  tore  out  deep  gullies  where  the 
ditch  had  been. 


Brush  or  Stone  Drains. 

Many  people  dug  ditches,  filled  them  partly  full  of  brush 
or  loose  stones  and  filled  the  top  of  the  ditch  with  earth. 
These  ditches  often  cave  in  and  fill  up  or  wash  out  until 
gullies  are  formed.  However,  many  people  still  believe  that 
such  drains  must  be  used.  Such  a  belief  rapidly  dies  out  when 
a  thorough  knowledge  of  the  advantages  of  tile  drainage  is 
acquired. 

By  means  of  tile  drainage  the  engineer  may  regulate  the 
height  of  the  water  table  to  suit  conditions.  By  so  doing  he 
allows  the  soil  to  become  aerated,  and  thus  the  roots  of  plants 
may   penetrate   to   a   great   depth. 

The  absence  of  the  free  water  near  the  surface  allows  the 
soil  to  warm  up  earlier  in  the  spring,  and  to  maintain  a  better 
tilth   throug-hout   the    season. 

In  laying  out  and  digging  ditches  for  tile  drains  the  gen- 
eral directions  should  be  followed  carefully.  The  bottom  of 
the  ditch  should  be  smoothed  by  means  of  a  tiling  hoe  or 
spoon.  The  tiles  are  then  laid  end  to  end  in  the  ditch  and 
a  little  fine  soil  is  carefully  tramped  on  top  of  them. 

The   ditch   may   now   be   filled   with   a  slip   scraper  or  by 


8o FARM  ENGINEERING 

hand.  The  earth  should  be  tamped  thoroughly  over  the  tiles, 
in  layers  not  more  than  six  inches  in  thickness;  this  will  prevent 
washouts. 

It  must  be  remembered  that  the  water  enters  the  tile 
drain  betweea  the  ends  o£  the  tiles.  Some  think  that  the 
water  soaks  through  the  tile.     The  latter  idea  is  incorrect. 

One  need  not  hesitate  to  use  either  cement  tile  or  vitri- 
fid  clay  tile  for  drainage  purposes,  and  even  though  the  ends 
are  placed  close  together,  the  water  finds  no  difficulty  in  rush- 
ing in  and  filling  the  line.  In  fact  great  care  must  be  taken 
to  have  the  ends  of  the  tile  forced  close  together.  This  pre- 
vents dirt  entering  the  tile.  Many  prefer  to  use  bell  end  tile 
in  place  of  square  end  tile  for  drainage  purposes.  This  makes 
the  work  more  expensive,  and  at  the  same  time  of  no  more 
real   value. 

In  those  localities  where  alkali  is  prevalent  the  vitrified 
tile  should  always  be  used,  as  the  alkali  "eats  up"  or  destroys 
the  ordinary  tile.  The  cement  tile  is  rapidly  destroyed  by 
alkali  unless  it  is  especially  treated  to  prevent  the  action  of 
alkali. 


Size    of    Tiles. 

In  theory  we  might  be  able  to  use  two  and  three  inch 
tile  for  our  short  drains,  but  in  actual  practice  we  have  ceased 
to  use  drains  smaller  than  four  inches  in  diameter.  It  is  hard 
to  say  just  what  size  tile  should  be  used,  but  the  following 
data  will  prove  advantageous  to  those  who  wish  to  use  tile 
drainage : 

A  four-inch  tile  will   drain  from  ten  to  fifteen  acres. 
A  five-inch  tile  will  drain  from  twelve  to  twenty  acres. 
A  six-inch  tile  will  drain  from  twenty  to  forty  acres. 
A  seven-inch  tile  will   drain   from   forty  to  sixty  acres. 
An  eight-inch  tile  will  drain  from  sixty  to  eighty  acres. 


FARM  ENGINEERING 


The  above  data  must  be  used  with  judgment  or  the  stu- 
dent may  find  that  he  is  putting  in  smaller  tile  than  he  should 
put  in.  He  seldom  finds  that  he  has  put  in  larger  tile  than 
he  should  put  in. 

It  should  be  remembered  that  the  carrying  capacity  of  a 
tile  is  approximately  proportional  to  the  square  of  the  diam- 
eter. Sonsequently  one  should  not  expect  two  four-inch  tiles 
to  fill  one  eight-inch  tile,  etc.,  etc. 


Joints. 

In  bringing  the  laterals  into  the  mains  we  should  always 
be  careful  to  see  that  the  water  does  not  approach  the  main 
at  right  angles.  It  should  gradually  approach  the  direction 
in  which  the  water  is  flowing  in  the  main  tile,  and  the  axis 
of  the  branch  should  be  level  with  the  axis  of  the  main  tile. 
In  other  words,  the  bottom  of  the  tiles  should  not  be  level. 


The  Tiling  Hoe. 

The  tiling  hoe  is  made  especially  to  smooth  the  bottom 
of  the  ditch,  leaving  a  round  for  the  tile  to  lay  in.  All  ditches 
should  be  smoothed  with  a  tiling  hoe. 


Ditch   Digging  Machines. 

Many  good  companies  are  now  building  machines  which 
dig  ditches  for  tile  drains,  at  exactly  the  right  level,  and  in 
some  cases  these  machines  smooth  up  the  bottom,  leaving  it 
round  for  the  tile.  The  Buckeye  ditcher  is  an  example  of 
this  type  of  machine. 

In  running  levels  for  tile  drains,  we  must  follow  the  same 
rules  as  we  use  in  digging  ditches  for  drainage  or  irrigation. 
The  same  method  of  measuring  oflf  and  staking  out  is  used 
as  in   drainage  and   irrigation  ditching. 


82  FARM  ENGINEERING 


EXAMINATION 


Note  to  Students — These  questions  are  to  be  answered  inde- 
pendently. Never  consult  the  text  after  beginning  your  exam- 
ination. Use  thin  white  paper  about  6  in.  x  9  in.  for  the  exam- 
ination. Number  the  answers  the  same  as  the  questions,  but 
never  repeat  the  question.      Mail  answers  promptly  when  com- 


1.  Explain  how  a  lack  of  knowledge  of  Agronomy  may  pre- 
vent an  Agricultural  Engineer  from  doing  successful 
work. 

2.  Explain  how  an  Agricultural  Engineer  must  be  governed 
by  the  principles  of  Farm  Management, 

3.  Describe  accurately  the  construction  of  a  surveyor's  level 
of  the  "Y"  type. 

4.  Discuss  errors  in  tape  measurements,  treating  of  Cumula- 
tive  and  Compensating -Errors, 

5.  Explain  how  to  turn  off  a  right  angle  by  means  of  the 
tape  and  pins. 

6.  If  the  surveyor  runs  a  line  at  90  degrees  to  the  direction 
of  the  compass  needle,  will  the  line  be  an  east  and  west 
line?     Why? 

7.  Explain  how  to  bring  the  level  bubble  tube  parallel  with 
the  bearings  of  the  "Y"  rings. 


FARM    ENGINEERING 83 

8.  Tell  how  the  area  of  a  field  with  straight  sides  of  irregular 
length,  and  angles  other  than  90  degrees,  may  be  de- 
termined. 

9.  Tell  how  the  area  of  an  irregular  field  may  be  determined 
with  a  planimeter. 

10.  Explain  how  to  cut  off  a  certain  number  of  acres  from  an 
irregular  field,  and  still  have  two  sides  of  the  new  field 
parallel  to  each  other. 

11.  Why  is  the  price  of  wood  fence  posts  increasing  from  year 
to  year? 

12.  Tell  how  to  make  a  cement  fence  post. 

13.  Tell  how  to  test  the  strength  of  a  cement  fence  post. 

14.  Why  are  god  culverts  and  bridges  necessary  on  the  farm? 

15.  Why  is  it  desirable  to  govern  the  temperature  and  mois- 
ture conditions  of  the  soil? 

16.  In  what  three  principal  ways  can  the  agricultural  engi- 
neer govern  the  temperature  and  moisture  conditions  of 
the  soil? 

17.  What  is  a  topography  map?  How  does  it  help  in  drain- 
age and  irrigation  projects? 

18.  Explain   the  principles  of  differential   leveling. 

19.  The  student  will  now  prepare  a  map  of  field  shown  in 
Plate  17.  and  with  a  cut  of  three  feet  at  X,  draw  in  dotted 
lines  a  proposed  drainage  system.  He  will  show,  (1)  di- 
rection of  drains;  (2)  length  of  drains  ;(3)  angles  turned 
off.  This  map  should  enable  any  engineer  to  locate  tile 
drains,  laid  according  to  the  map. 

20.  The  student  will  now  fill  in  the  following  page  of  notes, 
giving  the  grade  and  cut  at  each  100-foot  station.  The 
ditch  is  to  be  2  feet  deep  at  each  end,  and  run  on  even 
grade. 


84 


FARM  ENGINEERING 


Sta. 

S.  B. 

H.  I 

F.S. 

Elev. 

Grade 

Cut 

0 

4.50 

/'; 

.... 

10.00 

8.00 

2.00 

100 

5.21 

.... 

c      . 

200 

4.02 

•  • . . 

.  . 

300 

3.65 

.  , 

400 

3.46 

.  < . . 

,  , 

500 

3.21 

.... 

.  . 

600 

2.84 



2 

00 

21.  The  student  will  make  a  profile  map  showing  bottom  of 
ditch  and  top  of  ground. 

22.  Tell  the  two  main  sources  of  irrigation  water. 

23.  Describe  an  inverted  siphon  and  tell  how  it  works. 

24.  Define  the  second  foot  and  the  acre  foot  as  units  of  meas- 
ure of  irrigation  water. 

25.  Describe  the  cippoletti  weir  and  tell  how  it  should  be 
made  and  set. 

26.  Consult  Plate  29  and  weir  tables.  The  rod  reading  is  ex- 
actly .4  foot.  The  crest  of  the  weir  is  1  foot  long.  How 
many  cubic  feet,  or  what  part  of  a  cubic  foot  per  second  is 
passing  over  the  weir?  • 


Write  this  at  the  end  of  your  Examination 

I  hereby  certify  that  the  above  questions  were  answered  en- 
tirely by  me. 


Signed - 
Address 


THE, 

CORRESPONDENCE  COLLEGE 
OF  AGRICULTURE 

FARM   ENGINEILRING— Part  III 

HIGHWAY  ENGINEERING 

and 

FARM  CONCRETE  CONSTRUCTION 

by 

H.  BOYDEN  BONEBRIGHT  B.  S.  A.    MEMB.  A.  S.  A.  E. 

Agricultural  Engineer 

Montana  State  College  and  Experiment  Station 
BOZEMAN,  MONTANA 

This  is  the  third  of  a  series  of  three  books  giving  a  complete  course  of  instruction  in 

FARM  ENGINEERING 


NOTE   TO    STUDENTS 


In  order  to  derive  the  utmost  possible  benefit  from  this 
book  you  must  thoroughl}^  master  the  text.  It  is  not  in- 
tended that  you  should  commit  the  exact  words  to  memory, 
but  there  is  nothing  contained  in  the  text  which  is  not 
absolutely  essential  for  the  intelligent  farmer  to  know. 

For  your  own  good  never  refer  to  examination  questions 
until  you  have  finished  the  study  of  the  text.  By  follow- 
ing this  plan  the  examination  will  show  what  you  have 
learned  from  the  text. 

This  lesson  book  is  not  intended  to  be  a  book  of  plans 
for  the  building  of  roads  or  for  the  construction  of  concrete 
structures.  It  is  designed  to  give  in  the  most  practical 
possible  way,  the  fundamental  scientific  knowledge  which 
the  student  must  have  if  he  is  to  successfully  build  roads, 
or  concrete  work.  With  the  information  given  in  this  book 
the  student  should  be  able  to  design  for  himself  such  roads 
or  concrete  work  as  will  best  fit  the  conditions  under  which 
they  are  to  serve. 

Should  the  student  wish  to  buy  some  bo'oks  on  the  sub- 
ject of  Roads  and  Pavements  he  will  find  "Roads  and  Pave- 
ments" by  Ira  Osborn  Baker  to  be  an  excellent  addition 
to  any  engineering  dibrary.  "Highway  construction,"  by 
T.  Byrne,  is  also  an  excellent  reference  book.  These  books 
are  published  by  John  Eiley  &  Sons,  New  York.  Cost  five 
dollars  each. 

The  student  can  secure  for  the  asking  "Concrete  Con- 
struction about  the  Home  and  Farm"  from  the  Atlas  Port- 
land Cement  Co.,  30  Broad  St.  N.  Y.  "Concrete  Silos" 
and  "Concrete  in  the  Country"  from  The  Universal'Portland 
Cement  Co.,  Chicago,  111. 


Farm  Engineering   Part  III 


Highway  engineering  in  its  crudest  forms  has  been  practiced 
since  the  earliest  history  of  man. 

When  man  learned  the  fact  that  it  was  easier  to  walk  around 
a  hill  in  a  gradually  ascending  line  than  to  climb  directly  up  one 
side,  he  began  putting  into  practice  some  of  the  principles  which 
are  now  so  scientifically  worked  out  by  our  high  salaried  railroad 
and  highway  engineers. 

And  it  is  not  at  all  improbable  that  man  first  learned  the  prin- 
ciples of  rounding  the  hills  from  the  game  which  he  pursued,  for 
the  trails  of  many  wild  animals  show  that  even  the  beasts  of  the 
forests  understand  something  of  laying  out  roads  on  a  reasonable 
grade. 

Later  when  the  ass  and  the  ox  were  used  by  man  as  beasts 
of  burden  the  trails  had  to  be  widened  and  the  steepest  grades  had 
to  be  removed  from  the  trails. 

Then  the  crude  forms  of  carts  and  sleds  appeared  and  the  trails 
were  widened  into  roads.  While  thousands  of  years  have  elapsed 
since  these  crude  roads  began  to  scar  the  face  of  the  earth,  yet,  it 
remained  for  this  generation  to  witness  the  entrance  of  the  most 
destructive  vehicle,  which  roads  have  ever  been  made  to  carry. 
Heavily  loaded  wagons  and  traction  engines  may  crush  the  road's 
surface,  but  in  so  doing  they  only  serve  to  make  the  surface  harder. 
But  the  automobile  with  its  round  soft  tires  does  little  packing, 
and  in  fact  when  driven  at  a  moderate  speed  it  scarcely  injures  the 
road  at  all.  But  when  the  speed  is  increased  to  twenty  miles  an 
hour  the  dust,  the  sand,  and  even  the  small  pebbles,  fly  from  be- 
neath the  wheels  with  sufficient  force  to  carry  them  several  feet 
from  the  center  of  the  road. 

When  the  auto's  speed  increases  to  fifty  or  sixty  miles  per 
hour  the  material  is  literally  blown  from  beneath  the  tires  and  it 
falls  many  feet  from  where  it  originally  lay. 

Consequently  many  systems  of  road-building  which  served 
the  purpose  perfectly  for  thousands  of  years,  have  become  imprac- 
tical within  the  last  decade,  for  as  fast  as  the  road  surface  is  loos- 


FARM  ENGINEERING 


Plate  1.  In  plate  1  at  the  top  is  shown  an  automobile  wheel  traveling  at 
slow  speed.  Notice  that  no  dirt  is  being  thrown  from  beneath  the  tire. 
The  lower  part  of  the  plate  shows  a  wheel  (traveling  to  left)  at  high  speed. 
Notice  the  particles  of  earth  and  the  pebbles  falling  from  beneath  the  tire 
in  the  direction  of  camera.  (Of  course  this  picture  shows  a  blurred  wheel 
owing  to  the  speed  at  which  the  wheel  passed). 


FARM  ENGINEERING  5 

ened  by  the  calks  of  horses  and  the  wheels  of  slow  moving  vehicles, 
it  is  knocked  to  the  road-side  or  blown  into  an  adjoining  field  by 
the  swiftly  moving  automobiles. 

And  we  must  figure  that  the  automobile  has  come  to  stay. 
While  it  is  to  be  hoped  that  the  extreme  speed  of  some  of  our 
reckless  drivers  will  be  a  passing  fad,  we  must  reckon  with  the 
swiftly  moving  machines  as  among  the  worst  destroyers  of  old- 
fashioned  good  roads. 

In  order  to  properly  understand  the  subject  of  highway  engin- 
eering, we  must  have  very  definite  knowledge  of  several  sciences. 

Surveying. 

In  order  to  properly  lay  out  a  road  one  must  understand  the 
use  of  the  level  and  transit,  or  at  least  the  use  of  the  highway  or 
architect's  level.  With  these  instruments  the  highway  engineer 
lays  out  the  line  of  the  road,  and  determines  the  grades.  He  is 
also  able  to  stake  out  the  cuts  and  fills,  and  to  locate  the  side  ditches 
and  the  crown  in  the  middle  of  the  road. 

Drainage. 

One  of  the  most  essential  points  in  road  construction  is  proper 
drainage  of  the  land  through  which  the  road  runs,  and  especially 
that  land  directly  under  the  travelled  portion  of  it. 

Soils. 

For  the  following  reasons  it  is  essential  that  the  engineer  be 
able  to  judge  the  type  of  soil  over  which  he  lays  out  a  road. 

1st.  He  must  know  how  to  draiji  the  road,  and  the  type  of  soil 
has  much  to  do  with  the  problem  of  drainage. 

2nd.  He  must  be  able  to  tell  what  treatment  will  best  fit  the 
surface  for  heavy  or  light  traffic,  as  the  case  may  be. 

3rd.  He  must  be  able  to  foretell  what  eiTect  the  climate  will 
have  upon  the  soil  over  which  he  lays  out  a  road. 

4th.  .  He  must  be  able  to  determine  the  effect  of  swiftly  run- 
ning water,  not  only  on  the  road's  surface,  but  its  effect  upon  the 
side  ditches,  and  the  culverts  and  bridges  along  the  way. 

Animal  Husbandry. 

The  student  should  have  a  fair  idea  of  the  pulling  ability  of 
horses,  and  of  the  effect  of  different  road  surfaces  upon  the  feet  of 
horses. 


6  FARM  ENGINEERING 

Sanitary  Science. 

In  some  cases  roads  either  add  to  or  detract  from  the  sanitation 
of  a  district.  The  engineer  should  be  able  to  so  construct  the  roads 
that  they  will  aid  in  keeping  a  district  sanitary,  or  at  least,  not  in 
any  way  hinder  the  work  of  sanitation. 

Concrete  Construction. 

The  student  should  have  a  fair  idea  of  the  principles  of  con- 
crete construction  and  masonry,  in  order  that  he  may  design  and 
build  small  culverts  and  bridges  in  an  economical  and  satisfactory 
manner. 

Materials  of  Construction. 

The  student  should  have  a  fair  knowledge  of  the  materials  of 
construction  used  in  bridges  and  culverts. 

Sufficient  material  is  found  in  Part  1  to  enable  the  student  to 
figure  strengths  sufficiently  accurately  for  all  ordinary  work.  The 
student  must  always  figure  on  giving  road  structures  a  large  factor 
of  safety,  as  traction  engines  and  herds  of  farm  animals  often  sub- 
ject a  structure  to  from  10  to  20  times  the  normal  load. 

LAYING  OUT  ROADS 

In  the  laying  out  of  a  good  road  the  engineer  must  first  con- 
sider what  purpose  the  road  is  to  serve.  If  it  is  to  be  a  pleasure 
road,  then  he  need  not  seriously  consider  the  problems  which  relate 
to  shortening  distances  between  points,  but  aim  rather  at  cutting 
down  grades  by  means  of  contours,  rather  than  cuts  and  fills. 

In  the  case  of  tonnage  roads  he  should  aim  to  have  the  shortest 
possible  road  from  point  to  point,  and  at  the  same  time  cut  all 
grades  as  low  as  possible. 

In  many  states  it  has  become  a  habit  to  put  all  highways  upon 
section  lines.  This  is  often  very  bad  practice,  as  it  often  lengthens 
the  distance  between  points,  while  not  infrequently,  it  places  the 
road  in  such  a  position  that  deep  gulches  must  be  crossed,  and  high 
ridges  must  be  surmounted.  Such  construction  is  very  faulty  from 
the  standpoint  of  tonnage  roads. 

The  main  thoroughfares  into  our  larger  towns  and  cities  often 
carry  as  much  tonnage  as  some  of  the  less  important  railroads,  and 
there  is  no  good  reason  why  the  most  direct  route  should  not  be 


FARM  ENGINEERING  7 

taken  by  them,  even  though  some  land  had  to  be  acquired  by  con- 
demnation proceedings. 

Again,  by  properly  laying  out  a  road  we  can  avoid  steep  grader, 
and  thus  increase  the  efficiency  of  the  road  a  great  deal,  for  as 
"a  chain  is  no  stronger  than  its  weakest  link,"  so  the  efficiency  of  a 
tonnage  road  must  be  measured  by  its  steepest  grades  or  by  its 
poorest  bridges. 

It  is  unnecessary  to  take  up  here  the  subject  of  running  levels 
over  the  projected  highways  as  the  work  of  running  levels  is  dealt 
with  thoroughly  in  Part  II,  of  Farm  Engineering. 

Grade  of  Roads. 

In  laying  out  a  road  one  of  the  most  essential  points  is  the 
grade.  A  perfectly  level  road,  while  desirable  from  the  standpoint 
of  draft  of  vehicles,  is  not  desirable  from  the  drainage  standpoint. 
It  is  likel}^  to  become  a  mire  during  wet  seasons  of  the  year,  and 
when  it  once  becomes  a  mire  it  is  very  slow  about  drying  out. 

On  the  other  hand,  a  very  steep  grade  is  undesirable,  not  only 
on  account  of  the  increased  draft  of  ascending  vehicles,  but  also 
on  account  of  the  difficulty  of  maintaining  a  good  road  surface  dur- 
ing wet  weather.  The  washing  effect  of  hard  rains,  upon  the  steep 
grades  is  very  hard  to  overcome. 

How  Grades  Are  Computed. 

Many  authorities  speak  of  the  grade  of  a  road  in  terms  of  feet 
rise  per  hundred  feet  of  travel.  For  instance,  a  rise  of  one  foot  in 
traveling  one  hundred  feet  is  spoken  of  as  "a  grade  of  one  to  the 
hundred." 

Another  way  of  designating  the  amount  of  grade  is  in  per  cent. 
That  is,  if  the  rise  is  one  foot  in  a  hundred  feet  the  rise  is  said  to 
be  one  per  cent.  Five  feet  rise  per  hundred  feet  of  travel  is  a  five 
per  cent,  grade,  etc.,  etc. 

In  both  the  above  cases  the  actual  distance  traveled  is  taken  as 
the  basis  of  length  of  travel,  while  in  theory  the  distance  should 
be  taken  on  a  level,  yet  the  error  is  so  slight  that  most  authorities 
do  not  take  it  into  account.  Hence,  we  simply  measure  the  distance 
on  the  road  surface  and  divide  it  into  the  feet  of  rise  in  order  to 
get  the  grade. 

Effect  of  Grade  on  Draft  of  Vehicles. 

When  a  loaded  wagon  is  pulled  up  an  incline  the  power  re- 


8  FARM  ENGINEERING 

quired  to  move  it  becomes  greater,  due  to  the  fact  that  the  load, 
the  wagon,  and  the  source  of  power,  be  it  team,  or  engine,  must  be 
elevated  bodily  as  the  load  proceeds. 

Some  people  believe  that  the  actual  pull  required  to  move  a 
load  up  a  grade  varies  exactly  as  the  per  cent  of  the  grade.  This 
is  not  the  case,  because  there  are  other  factors  which  enter  into  the 
total  pull  of  a  loaded  vehicle. 

Axle  Friction. 

A  certain  amount  of  power  is  required  to  cause  the  wheels  to 
revolve  upon  the  axles,  or  in  case  of  sleds,  power  is  required  to 
cause  the  runners  to  slip  upon  the  snow  or  ice. 

The  amount  of  axle  friction  is  generally  from  five  to  ten  per 
cent  of  the  total  pull  of  a  vehicle  when  running  upon  a  level  road. 
Rolling  Friction. 

What  really  causes  by  far  the  greater  part  of  the  draft  of  ve- 
hicles, is  the  fact  that  the  wheels  actually  crush  into  the  surface 
of  the  earth  and  thus  as  they  proceed  they  keep  smashing  down 
the  earth  in  front  of  the  wheels.  In  general  rolling  friction  ac- 
counts for  about  90  per  cent  to  95  per  cent  of  the  total  draft  of 
vehicles  on  level  roads. 

T  Tt  J^ 


Plate  2.  Figure  1  represents  lightly  loaded  wagon  wheel  running  upon  a 
hard  road.  Figure  2  represents  heavily  loaded  wagon  wheel  running  upon 
a  soft  level  road.  Figure  3  represents  a  heavily  loaded  wheel  running  up 
a  steep  grade  upon  a  soft  road.  Notice  the  marked  increase  in  "rolling 
resistance"  shown  of  2  over  1  and  added  to  the  rolling  resistance  of  2  we  find 
grade  resistance  in  3. 

Of  course,  on  hard  roads  the  axle  friction  remains  nearly  the 
same,  while  the  rolling  friction  decreases.  Thus  the  per  cent  of  the 
axle  friction  is  greater  on  hard  roads  and  smaller  on  soft  roads, 


FARM  ENGINEERING  9 

while  the  total  draft  of  the  vehicles  is  smaller  on  hard  roads  and 
greater  on  soft  roads. 

This  explains  the  fact  that  a  good  team  often  has  great  diffi- 
culty in  moving  a  two-ton  load  over  a  soft  earth  road,  while  an 
equally  good  team  can  easily  haul  a  four  or  five  ton  load  over  a 
hard  paved  street. 

Now  when  the  student  realizes  that  the  axle  friction  and  the 
rolling  friction  do  not  diminish  when  a  vehicle  is  drawn  up  a  grade, 
he  will  readily  understand  why  so  much  power  is  required  in  haul- 
ing heavy  loads  over  steep  grades. 

The  following  table  gives  approximately  the  draft  of  loaded 
wagons  over  different  types  of  roads. 

Pull  in  pounds  per  ton  of  weight  moved: 

Good   macadam   road 75  to  110 

Sandy   road   with    hard    bottom .150  to  200 

Good  hard  earth  road 75  to  150 

Soft   earth   road 150  to  300 

Plowed  ground  hard  bottom 500  to  800 

This  may  increase  to  nearly  the  weight  of  the  load  in  case  the 
road  becomes  soft  enough. 

The  student  should  understand  clearly  that  nearly  every  type 
of  road  offers  a  different  rolling  resistance.  Hence,  no  exact  data 
can  be  given  which  can  be  used  in  all  cases.  And  what  is  more, 
the  rolling  resistance  will  vary  in  the  same  soil  under  different 
climatic  conditions. 

Not  only  do  we  look  to  the  grade  resistance,  the  rolling  resist- 
ance, and  the  axle  resistance  to  interfere  with  the  progress  of  a 
team,  but  the  horses  must  lift  their  own  weight  at  a  disadvantage. 
As  the  muscular  effort  of  a  horse  while  pulling  is  nearly  all  in  the 
hind  legs  and  loin,  the  front  of  the  horse  is  only  of  sufficient  weight 
to  keep  the  front  feet  from  leaving  the  ground.  When  the  horse 
attempts  to  pull  up  a  steep  grade,  the  front  feet  leave  the  ground 
before  his  best  effort  can  be  made. 

The  same  is  true  of  traction  engines.  In  many  types  of  engines 
there  is  great  danger  of  the  front  end  rising  from  the  ground  while 
ascending  steep  grades. 

Were  it  possible  to  select  grades  of  any  desired  pitch  the  aver- 
age engineer  would  probably  select  a  grade  of  from  one-tenth  foot 


10  FARM  ENGINEERING 

to  one-half  foot  per  hundred.  This  affords  g-ood  drainage  and  does 
not  increase  the  grade  resistance  to  a  point  where  it  will  become 
troublesome.  We  find  a  great  many  long  and  troublesome  hills 
which  have  grades  as  steep  as  eight  feet  per  hundred  feet.  Gener- 
ally they  are  not  considered  serious  impediments  to  traffic.  A  ten 
per  cent  grade  is  generally  considered  practical  if  not  too  long.  A 
fifteen  to  twenty  per  cent  grade  should  never  be  tolerated  in  a  ton- 
nage road  unless  the  length  of  pull  can  be  restricted  to  less  than 
100  yards.  In  such  cases  it  is  usually  possible  to  reduce  the  grade 
by  cut  and  fill  or  by  making  the  road  to  follow  a  contour  around 
the  hill. 

Grades  of  fifteen  to  twenty  per  cent  are  not  only  hard  to  ascend 
but  they  are  very  dangerous  of  descent  as  well. 

However,  in  mountainous  parts  of  the  country  we  find  roads 
in  which  grades  as  steep  as  twenty  per  cent  are  not  infrequent. 
In  such  localities  vehicles  are  usually  of  stronger  construction 
than  those  used  upon  the  more  nearly  level  roads. 

We  have  the  "mountain  wagon"  in  place  of  the  surrey,  and  the 
"mountain  gear"  in  place  of  the  lighter  "valley  gear"  in  our  lumber 
wagons. 

Special  automobiles  with  low  gears  suitable  for  mountain  roads 
are  now  furnished  by  many  companies. 

Traction  engines,  as  a  rule,  have  no  trouble  in  ascending  grades 
too  steep  for  travel  by  horses  which  are  pulling  heavy  loads. 

Regarding  the  descent  of  steep  grades  in  mountainous  sections 
of  the  country,  each  vehicle,  even  to  the  lightest  buggy,  is  equipped 
with  a  powerful  brake.  The  sleds  are  equipped  with  "rough-locks" 
and  of  course  the  traction  engines  and  automobiles  have  the  reverse 
gear  as  a  last  resort  in  case  the  brakes  do  not  serve  the  purpose. 
The  above  facts  are  not  intended  as  excuses  for  extremely 
steep  grades  in  mountain  roads.  The  engineering  is  faulty,  but  in 
many  cases  the  roads  do  not  carry  sufficient  tonnage  to  warrant  cut- 
ting the  grades  at  great  expense. 

Width  of  Highways. 

In  general  the  width  of  highways  is  determined  by  the  laws 
of  the  state  rather  than  by  the  judgment  of  the  engineer.  Many 
states  require  the  highway  to  be  66  feet  or  4  rods  wide  between 
fences. 


FARM  ENGINEERING 


11 


In  a  great  majority  of  cases  the  roads  need  not  be  this  wide. 
The  actual  graded  surface  is  nearly  always  decided  by  the  highway 
engineer.  While  many  roads  of  little  importance  are  built  from 
20  to  24  feet  wide  it  is  a  general  practice  to  use  about  30  to  34  feet 


Plate  3.  "Four-wheeled  drive"  tractor  ascending  64  per  cent,  grade.  In 
general,  tractors  have  little  difficulty  in  climbing  a  steep  hill  which  affords 
a  good  foothold  or  grip. 

for  the  graded  portion.  That  is,  from  the  center  of  one  ditch  to  the 
center  of  the  other.  The  matter  of  width  must  be  left  to  the  judg- 
ment of  the  engineer. 

Crown  of  the  Road  Surface. 

In  order  that  moisture  may  be  made  to  run  off  the  traveled 
portion  of  a  road  the  center  is  usually  raised  higher  than  the  sides. 
The  height  of  the  crown  above  the  bottom  of  the  side  ditches  varies 
from  4  to  18  inches.  From  5  inches  in  a  narrow  road  to  10  inches 
in  a  wide  road  is  considered  good  practice  for  earth  roads. 

The  crown  should  be  rounding,  not  sharp,  and  the  side  ditches 
should  have  slanting  sides.  Nature  tends  to  destroy  the  sharp 
angles  of  earth  surfaces  and  the  sharp  banks  of  a  road  ditch  are 
no  exception  to  the  rule. 


12 


FARM  ENGINEERING 


Besides  the  natural  agencies  which  tend  to  cave  in  the  banks, 
we  also  have  a  very  great  action  from  animals  and  vehicles.  By 
smashing  the  sharp  banks  into  the  ditch  they  fill  up  that  portion 
wherein  the  drainage  water  should  move  freely.  Thus,  the  sharp 
banks  prove  very  faulty  in  road  construction.  The  rounded  ditches 
with  sloping  banks  are  little  harder  to  make  and  serve  the  purpose 
much  better.  In  every  case  in  which  the  slope  of  the  land  is  not 
excessive  the  dirt  which  is  used  to  make  the  crown  of  the  road 


Plate  4.  In  the  case  of  Fig.  1,  Plate  4,  the  side  ditches  have  sharp  angles 
at  a  and  a.  Such  ditches  soon  crumble  in  and  become  useless.  In  Fig  2, 
Plate  4,  we  see  sloping  ditches  at  b  and  b.  These  sloping  ditches  remain 
in  good  condition  for  a  long  time.  They  do  not  hinder  the  dragging  or  the 
grading  of  the  road. 

should  be  equal  in  quantity  to  that  removed  from  the  ditches. 
Thus,  no  dirt  need  be  moved  lengthwise  upon  the  road.  In  other 
words  the  cut  in  the  ditches  equals  the  fill  of  the  crown. 

Drainage  of  Roads. 

One  of  the  serious  factors  which  must  be  considered  by  the 
highway  engineer  is  the  drainage  of  roads. 

It  is  not  a  hard  matter  to  keep  roads  reasonably  dry  during 
favorable  seasons  of  the  year  by  having  properly  constructed  side 
ditches.  Many  people  attempt  to  drain  roads  by  putting  tile  drains 
under  the  middle  of  the  road's  crown.  The  ditch  which  is  dug  for 
the  tile  drain  usually  proves  troublesome  for  several  years.  And 
as  it  becomes  hard,  packed  and  puddled,  the  efficiency  of  the  tile  is 
diminished.  As  a  matter  of  fact  the  real  efficiency  of  such  a  tile 
is  never  very  high. 


FARM  ENGINEERING 


13 


If  the  tile  be  placed  under  one  or  both  of  the  side  ditches  the 
results  are  much  better.     This  is  true  for  two  reasons. 

1st.  The  crown  of  the  road  tends  to  cause  the  surface  water 
to  run  to  the  side  ditches  where  it  soaks  directly  down  to  the  tile 
drain. 


Plate  5.  In  Fig.  1,  Plate  5,  is  shown  a  useless  attempt  to  drain  a  road  by 
means  of  a  tile  running  in  the  center  of  the  road.  As  the  soil  is  puddled  and 
as  the  center  of  the  road  is  high,  the  water  must  run  to  the  side  ditch  and 
soak  through  the  ground  to  the  tile.  In  Fig.  2,  Plate  5,  we  see  a  tile 
placed  under  side  ditch  where  the  water  can  easily  reach  it.  The  auxiliary 
open  ditch  "x"  and  the  tile  "z"  are  sometimes  used  to  cut  off  washing  and 
seepage  on  side  hills.  The  open  drain  "x"  is  very  valuable  for  catching 
the  wash  of  severe  rains  while  the  tile  "z"  serves  to  drain  the  soil  in  case 
the  side  hill  has  wet  seepy  spots  or  springs  in  it. 

2nd.  Because  the  earth  in  the  ditches  is  not  packed  so  hard 
as  the  earth  on  the  crown  of  the  road. 

In  case  of  side  hills  it  is  well  to  do  all  the  tile  draining  on  the 
Upper  side  of  the  road.  This  prevents  water  from  rushing  upon  the 
crown  of  the  road  during  the  heavy  rains  and  it  also  prevents  see- 
page water  from  keeping  the  surface  of  the  road  wet  between  rains. 

A  large  ditch  near  the  fence  on  the  upper  side  of  the  road  often 


14 


FARM  ENGINEERING 


proves  of  great  value,  as  it  catches  flood  waters  which  come  down 
from  the  adjoining  hillside. 

In  case  of  wet,  seepy,  or  springy  hillsides  a  tile  drain  laid  along 
the  upper  fence  often  intercepts  the  flow  of  ground  water  and  thus 
keeps  the  road  dry.. 


^-.  f- 


._»^,.-.v 


Plate  6.     A  little  scientific  road  drainage  would  have  prevented  this  con- 
dition of  the  road  shown  in  the  plate. 

In  rare  cases  it  becomes  necessary  to  secure  permission  to  put 
drains  into  adjoining  fields  in  order  to  keep  roads  dry,  but  this  is 
seldom  the-  case. 

Culverts. 

"Where  does  all  this  drainage  water,  of  which  we  have  been 
speaking,  go  to?"  we  ask. 

In  each  locality  there  is  a  general  drainage  system  that  must 
be  made  use  of.  A  creek,  a  branch  of  a  river  or,  perhaps  a  river. 
The  drainage  water  must  be  conducted  to  some  such  outlet. 

In  case  the  road  crosses  a  low  spot  or  an  undrained  marsh, 
it  is  usually  advisable  to  build  an  embankment  upon  which  the  road 
may  be  located. 


FARM  ENGINEERING  15 

It  often  pays  to  investigate  the  nature  of  the  soil  beneath  these 
sink  holes.  If  "hard  pan"  or  an  impervious  layer  of  clay  is  found 
a  few  feet  below  the  surface  and  below  this  "hard  pan"  a  layer  of 
gravel,  or  loose  earth  is  located,  it  is  often  possible  to  "shoot  the 
hard  pan"  with  dynamite  and  thus  allow  the  drainage  water  to  seep 
down  into  the  subsurface  soil  and  flow  away. 

In  draining  a  piece  of  road  in  this  way  the  engineer  often 
drains  much  valuable  land  by  the  road  side.  In  many  cases  it  is 
better  practice  to  build  a  road  around  a  swamp  rather  than  to  dyke 
it.  The  land  is  seldom  very  valuable  in  the  neighborhood  of  a 
swamp,  and  the  road  bed  is  cheaper  and  often  far  more  satisfactory 
when  located  on  the  banks  about  the  swamp.  It  is  always  advisable 
to  place  culverts  under  the  roads  which  traverse  low  swaxnpy 
ground.  While  there  may  be  no  apparent  movement  of  water  in 
the  swamp  yet  rains  and  seepage  are  likely  to  cause  water  moxe- 
ments  from  one  side  to  the  other.  Thus,  the  culvert  often  sa\xs 
washouts  and  much  trouble. 

Culverts. 

The  side  ditches  or  the  tile  drains  bring  the  water  down  the 
grades  of  a  road  to  the  lower  places.  It  often  becomes  necessary 
to  conduct  the  water  from  one  side  of  the  road  to  the  other.  This 
is  done  by  means  of  culverts.  A  culvert  is  simply  a  small  bridge 
It  must  be  sufficiently  strong  to  carry  the  heaviest  loads,  and  suffi- 
ciently large  to  carry  the  water  from  one  side  of  the  road  to  the 
other  without  allowing  any  of  the  water  to  flow  across  the  road  bed. 

Culverts  are  made  of  various  materials. 

1st.     Stone  culverts  are  of  two  general  types. 

A.  The  box  culvert  which  consists  of  two  parallel  walls  built 
across  the  road.  On  top  of  these  and  reaching  from  one  wall  to 
the  other  large  flat  stones  are  laid.  The  whole  is  covered  with  dirt 
and  the  culvert  is  complete.  These  culverts  are  "laid  up  dry"  (that 
is,  without  mortar),  with  lime  mortar,  or  cement  mortar.  The  latter 
is  by  far  the  best  of  the  three  types. 

B.  The  arch  culvert  consists  of  two  walls  which  are  put  par- 
allel to  each  other  at  the  base  and  the  tops  are  so  laid  as  to  form 
nearly  a  semi-circle  at  the  top.  There  are  many  t3^pes  of  arches 
but  they  all  embody  the  one  principle.  Each  stone  is  so  laid  that 
it  resists  compression  stress,  and  not  bending  stress. 


16 


FARM  ENGINEERING 


As  in  the  case  of  the  box  culvert  the  arches  are  laid  "dry",  with 
lime  mortar,  or  with  cement  mortar.  When  it  comes  to  carrying 
heavy  traction  engines  the  arch  usually  proves  superior  to  the  box 
type  of  stone  culvert,  as  these  heavy  motors  often  exert  a  pressure 
of  many  tons  upon  one  "lug"  or  "grouter".  If  this  stress  be  exerted 
upon  the  middle  of  one  of  the  flat  stones  of  a  box  culvert,  there  is 
likely  to  be  a  smashed  culvert.    While  stone  is  very  strong  in  com- 


Plate  7.  In  Plate  7,  Fig.  1,  is  shown  section  of  stone  box  culvert.  Notice 
that  the  top  stone  acts  as  a  common  beam;  Fig.  2  is  a  section  of  an  arch 
culvert  or  stone  repression;  Fig.  3  a  box  concrete  culvert;  Fig.  4  an  arch 
concrete  culvert;  Fig.  5  a  monolithic  round  culvert  made  without  the  use 
of  regular  outside  forms.  In  the  cases  of  1,  2,  3  and  4  the  side  walls  have 
footings  and  the  bed  of  the  stream  is  covered  with  stones  to  prevent 
washing. 

pression  it  is  not  very  strong  or  very  reliable  when  subjected  to 
bending  stresses.  For  this  reason  the  arch  culvert  is  generally 
more  satisfactory  than  the  box  culvert. 

Concrete  Culverts. 

One  of  the  most  satisfactory  materials  for  the  building  of  cul- 
verts is  concrete.  It  is  easily  made  in  the  right  shape,  it  is  not  ex- 
tremely expensive  and  it  is  probably  the  most  durable  material  now 
available  for  culverts. 


FARM  ENGINEERING 


17 


Types  of  Concrete  Culverts. 

The  box  type  of  culvert  has  met  with  favor  in  some  sections. 
The  side  walls  usually  have  an  extension  or  "footing"  at  the  bottom. 
The  top  must  be  heavily  reinforced  in  order  to  prevent  it  from 
breaking-  down.  The  heavy  slab  of  concrete  which  forms  the  top 
has  bars  extending  from  side  to  side  of  the  culvert,  cast  into  the 
concrete.  The  bars  are  usually  about  one  inch  to  one  and  one-half 
inches  from  the  lower  surface  of  the  slab.  Thus,  the  iron  bars'  pull 
and  the  concrete  material  at  the  top  of  the  slab  must  take  on  equal 
stress  in  compression. 


3r 


j2zr 


TZ2zr 


Plate  8.  In  Plate  8,  Fig.  6,  we  see  a  section  of  a  plank  box  culvert.  The 
plank  needs  but  to  be  split  to  render  the  culvert  worthless.  Fig.  7  shows 
how  cross  timbers  may  be  mortised  into  the  side  planks  in  order  to  give 
the  top  plank  support  from  beneath.  Fig.  8  shows  how  the  top  and  bottom 
planks  may  be  cut  into  three  pieces  and  laid  across  the  culvert.  This,  is 
the  best  of  the  three  types  but  at  that,  it  is  a  rather  short-lived  culvert. 
Fig.  9  is  a  tile  culvert  with  bell  and  tile.  Fig.  10  is  a  corrugated  sheet  steel 
culvert.  Fig.  11  is  a  cast  iron  or  sheet  steel  arch.  Notice  that  all  of  these 
culverts  are  placed  well  down  beneath  the  surface  of  the  road. 

A  far  more  popular  culvert  is  the  concrete  arch.  The  material 
is  so  placed  that  each  part  is  in  compression.  In  theory,  the  smaller 
arches  do  not  require  reinforcement,  but  in  actual  practice  it  is  a 
good  plan  to  reinforce  the  work  throughout  with  steel  reinforcing 
bars  or  with  heavy  woven  wire  fence.  Such  fence  as  "The  Electric 
Weld"  and  the  "Page"  fence  give 'excellent  results  when  used  as 
reinforcing  material  for  small  arches. 


18 


FARM  ENGINEERING 


Probably  the  cheapest,  the  most  easily  made  and  one  of  the 
most  satisfactory  concrete  culverts  is  the  round  monolithic  culvert. 
This  is  a  culvert  of  one  piece  of  concrete.  In  most  cases  the  ground 
is  prepared,  and  a  heavy  layer  of  concrete  is  thrown  into  the  trench, 
the  form,  v^hich  is  nothing  more  than  a  round,  collapsible  sheet-iron 
tube,  is  then  laid  upon  the  fresh  concrete.  The  concrete  is  placed 
about  the  sides  of  the  mold  and  over  the  top.  In  a  few  days  the 
concrete  sets,  and  by  some  patent  device  the  mold  is  made  to  be- 
come smaller  in  diameter.  It  is  then  withdrawn  and  earth  is  placed 
over  the  culvert.  Such  culverts  should  be  reinforced  with  rods  or 
woven  wire. 

All  cement  culverts  should  be  coated  with  neat  cement  (pure 
cement)  mixed  in  water.  Some  call  this  material  "cement  paint", 
"cement  whitewash"  or  "cement  wash".  It  is  applied  with  a  brush 
and  it  renders  the  surface  of  the  work  water-proof. 

Small  Wooden  Culverts. 

For  a  great  many  years  wooden  culverts  were  more  popular 
than  any  other  type.  This  is  no  doubt  due  to  the  fact  that  they 
were  cheap  and  quickly  constructed. 

In  case  of  the  box  culvert  a  common  system  is  to  spike  four 


'  i^A. 


Plate  9.  The  large  culvert  or  bridge  shown  in  this  plate  had  poor  wooden 
wing  walls  which  allowed  the  water  to  leak  through  and  wash  out  the  dirt 
back  of  the  side  walls.  The  "cave-in"  came  at  the  first  heavy  rain  after 
the  installation.  Proper  wing-walls  and  a  proper  tamping  and  puddling  of 
the  soil  back  of  the  side  walls,  would  have  made  a  good  job  out  of  a  bad  one. 


FARM  ENGINEERING 


19 


planks  together  in  such  a  way  that  one  plank  lies  upon  the  earth, 
two  others  set  upon  edge,  rest  Lipon  the  first  plank  and  form  the 
sides  of  the  culvert.  Another  is  then  laid  upon  the  two  side  planks 
in  such  a  manner  as  to  form  a  top.  Now  all  that  is  necessary  to 
break  down  such  a  culvert  is  to  split  the  top  plank.  The  weight  of 
traction  engines  will  do  this  regularly  unless  there  be  plenty  of 
dirt  over  the  culvert. 

In  some  cases  heavy  hard  wood  cross  pieces  are  laid  under  the 
upper  plank  and  mortised  into  the  side  planks.  This  improves  the 
culvert  about  100  per  cent. 

A  still  better  system  is- to  cut  the  top  and  bottom  planks  into 
short  pieces  and  lay  them  crosswise  on  the  ground  for  the  bottom 
and  on  top  of  the  side  planks  for  the  top. 

All  the  above  mentioned  wood  culverts  are  all  right  when  new 
if  they  be  properly  made  and  set.  But  when  they  become  slightly 
rotted,  they  are  poor  excuses  for  culverts. 

Large  Wooden  Culverts. 

In  the  building  of  the  larger  types  of  wood  culverts  it  is  com- 
mon to  drive  posts  or  piles  into  the  creek  bottom.     Planks  are  then 


••«jA«i^ 


■■£msit^^ 


Plate  10.  An  arch  culvert  and  wings  made  in  one  piece  (monolithic)  of 
concrete.  When  the  workmen  are  ready  to  remove  the  inside  forms,  they 
will  move  the  lower  cross  beam  after  which  they  can  remove  the  sides  and 
top  of  the  arched  form. 


20 


FARM  ENGINEERING 


spiked  to  these  piles  on  the  outsides  and  some  wooden  stringers  are 
placed  upon  the  tops  of  the  piles.  Planks  are  then  laid  upon  the 
stringers  and  after  the  earth  work  is  filled  in  against  the  sides  of 
the  bridge  it  is  complete.  It  is  much  better  to  substitute  two  or 
three  of  the  round  concrete  culverts  placed  side  by  side  for  these 
larger  wooden  culverts. 

It  is  quite  possible  to  so  build  the  two  or  three  monolithic  cul- 
verts that  they  are  all  made  of  one  large  piece  of  reinforced  con- 
crete. Such  a  culvert  does  not  wash  out  easily  and  it  will  last  a 
life  time. 

Steel  and  Iron  Culverts. 

It  has  become  common  of  late  years  to  substitute  a  piece  of 
"corrugated  steel  pipe"  for  the  concrete  or  stone  culvert.    The  price 


Plate  11.  A  very  large  corrugated  steel  culvert  installed  under  a  high  fill. 
Notice  the  very  heavy  retaining  wheel. 

of  these  steel  culverts  is  reasonable  and  they  are  easy  to  locate. 
They  last  a  long  time  when  properly  made  and  galvanized.  A  good 
method  of  setting  such  a  culvert  is  to  build  the  wings  of  concrete 
and  to  cover  the  entire  iron  culvert  with  concrete.  Such  a  com- 
bination makes  a  good  culvert  after  the  iron  has  rusted  out. 

Many  tjq^es  of  steel  and  cast  iron  arch  culverts  are  now  on  the 


FARM  ENGINEERING 


21 


market.  When  properly  set  they  give  excellent  satisfaction,  but  it 
too  often  happens  that  the}^  are  not  given  a  good  foundation.  Thus, 
eventually  they  warp  and  in  some  cases  give  away.  It  is  a  good 
plan  to  cover  such  an  arch  with  a  heavy  wall  of  concrete.  Thus 
you  will  get  a  concrete  backing  to  the  sheet  metal. 


Plate  12.     A  cast-iron  sectional  culvert  in  process  of  erection.     Notice  that 
a  metal  wing-wall  and  a  metal  bottom  are  provided. 

Tile  Culverts. 

Culverts  are  often  built  of  tiles.  These  tiles  are  sufficiently 
large  and  strong  to  carry  the  weight  of  all  types  of  vehicles  and 
motors.  The  proper  setting  is  absolutely  necessary  if  tile  culverts 
are  to  be  successful.  This  is  taken  up  more  fully  under  "setting  of 
culverts." 

Perhaps  the  poorest  kind  of  tile  for  culverts  is  the  red,  unglazed 
clay  tile.  As  this  t3^pe  readily  absorbs  water  it  is  very  likely  to 
disintegrate  when  subjected  to  freezing  and  thawing.  Concrete 
tile,  when  made  porous,  is  also  inclined  to  disintegrate  in  the  same 
manner  as  unglazed  clay  tile.  Well  glazed  "bell  end"  clay  tile  are 
very  satisfactory  for  culverts,  as  are  water-proof  cement  tile. 

Cast  iron  tile  are  now  being  used  extensively  by  railroads  and 
they  make  a  most  excellent  culvert. 


22 


FARM  ENGINEERING 


SETTING  CULVERTS 


It  is  one  thing  to  select  a  good  type  of  culvert,  and  it  is  very 
decidedly  another  thing  to  set  it  as  it  should  be  set. 

The  author  has  ample  opportunity  to  study  poor  methods  of 
setting  culverts  and  in  most  cases  the  opportunities  are  less  wel- 
come than  instructive.    A  few  of  the  most  common  faults  are : 

1.  Wrong  location. 

2.  Culvert  too  small. 

3.«  Culvert  not  set  deep  enough. 

4.  Culvert  not  protected  by  wings. 

5.  Culvert  not  properly  tamped  and  puddled  when  set. 


'**j>**.ii^«*S#^^^ 


T^^^^^^?^^^^' 


Plate  13,  The  culvert  shown  in  Plate  13  was  not  protected  by  wing-walls. 
It  was  not  tamped  or  puddled  on  the  sides.  A  few  days  after  the  photo 
was  taken,  it  was  washed  out  and  down  stream. 

Wrong  Location. 

It  would  seem  rather  foolish  to  lay  down  a  law  requiring  road 
commissioners  to  place  the  culverts  where  the  water  could  flow 
through  them,  yet  we  often  find  culverts  so  far  up  on  the  side  of  a 
hill  that  the  water  must  seep  through  or  run  over  the  road  way, 
or  else  run  up  hill  to  get  to  the  culvert.  This  trouble  is  usually  due 
to  some  so-called  practical  man  "using  his  eye"  to  locate  the  lowest 
point  in  the  hollow  or  ravine.  The  use  of  a  level  would  eradicate 
the  difficulty.     It  is  needless  to  say  that  drainage  culverts  should 


FARM  ENGINEERING  23 

be  placed  so  that  drainage  water  will  flow  to  and  through  them. 
Irrigation  ditch  culverts  must  be  placed  at  such  points  as  will  pre- 
serve the  proper  grades  of  the  ditches.  Thus,  in  some  parts  of  the 
country  we  find  nearly  all  the  irrigation  ditch  culverts  on  the  high- 
est parts  of  the  roads. 

Culvert  Too  Small. 

It  is  a  foolish  custom  among  some  road  supervisors  to  choose 
a  size  of  culvert  and  use  it  regardless  of  the  amount  of  water  it 
must  carry.  It  is  next  to  impossible  to  tell  an  engineer  how  large 
a  culvert  should  be,  because  of  the  fact  that  the  culvert  must  carry 
floods.  Whenever  possible  it  is  well  to  measure  the  sectional  area 
of  a  stream  at  its  highest  flood  and  then  design  the  culvert  to  carry 
from  one  and  one-half  to  two  times  the  amount. 

By  using  this  method  it  is  often  found  necessary  to  use  cul- 
verts which  seem  very  large,  but  when  such  a  culvert  is  once 
installed  properly  it  eradicates  future  trouble  once  for  all. 

To  determine  the  cross  section  of  a  flood  stream  it  is  not  neces- 
sary to  get  into  the  water  during  the  flood.  Simply  mark  the  points 
to  which  the  water  reaches  upon  the  banks,  then  after  the  flood 
subsides,  determine  by  level  how  deep  the  water  was.  Then  the 
width  of  the  stream  at  the  flood  time  may  be  determined  with  a 
tape  and  the  approximate  number  of  square  feet  of  its  cross  section 
may  be  determined. 

It  is  often  possible  to  get  from  some  neighbor  a  rather  accurate 
statement  of  how  far  the  stream  overflows  its  banks  at  flood  time. 
From  this  a  fair  estimate  can  be  obtained  of  the  cross  section  of 
the  stream. 

The  cross  section  should  be  determined  at  or  near  the  location 
of  the  new  culvert,  otherwise  it  is  of  little  use.  After  the  area  is 
determined  the  size  of  the  culvert  may  be  determined.  For  rect- 
angular box  culverts  the  approximate  height  may  be  assumed  and 
the  cross  section  area  divided  by  the  height  will  give  the  width. 
Now  if  an  allowance  of  one  and  one-half  is  used,  simply  add  one- 
half  the  width  of  the  culvert  to  its  computed  width  and  the  result 
will  be  the  actual  width  of  the  culvert.  In  case  an  allowance  of 
twice  the  cross  section  is  used,  simply  multiply  the  cross  section 
of  the  stream  at  flood  by  two  and  divide  by  the  height  of  the  cul- 
vert.   In  C3,se  of  round  culverts,  the  cross  3ection  area  should  first 


34  FARM,  ENGINEERING 

be  divided  by  three  and  one-seventh.  By  extracting  the  square  foot 
of  the  ansv^er,  v^e  get  the  radius,  or  one-half  the  diameter  of  the 
culvert. 

In  case  the  round  culvert  would  be  too  large,  the  cross  section 
may  be  divided  into  tvv^o,  or  three  parts  and  the  culverts  may  be 
laid  side  by  side. 

In  case  of  arch  culverts  all  that  is  necessary  is  to  consider  that 
portion  of  the  cross  section  w^hicli  has  parallel  vv^alls  as  a  rectangle 
and  the  arched  portion  as  a  semi-circle.  The  sum  of  the  areas  of 
the  semi-circle  and  the  rectangle  w^ill  be  the  total  area  of  the  cul- 
vert. 


Plate  14.  In  Plate  14,  we  see  a  cross  section  of  a  culvert  Avhich  was  not 
placed  deep  enough  to  be  satisfactory.  Notice  that  the  top  of  the  opening 
is  far  above  the  low  spots  in  the  road  as  indicated  by  the  dotted  line.  The 
top  plank  is  exposed  to  traffic.  The  top  of  the  culvert  should  have  been 
lower  than  the  dotted  line. 

Not  all  arches  are  semi-circles  but  the  result  will  be  near 
enough  for  satisfactory  results  in  case  of  culverts. 

Culverts  not  set  deep  enough. 

Many  people  fail  to  place  culverts  low  enough  in  the  ground 
to  allow  the  water  to  run  through  the  culvert  without  passing  over 
the  road  bed.  This  is  poor  practice.  In  case  of  a  deep  fill  it  is  gen- 
erally good  practice  to  put  the  culvert  at  the  bottom  of  the  em- 
bankment so  that  no  water  is  allowed  to  collect  on  the  upper  side 
of  the  embankment. 

Culvert  Not  Protected  by  Wings. 

It  is  good  practice  to  protect  the  culvert  by  "retaining  walls" 
or  wings  at  both  fhe  upper  and  lower  ends.  These  wings  should  be 
nearly  water  tight,  in  order  to  prevent  the  water  running  in  and  cut- 
ting away  the  earth  at  the  sides  of  the  culvert.  It  is  well  to  have 
the  wings  extend  at  an  angle  up  the  stream  at  the  upper  end  and 
down  stream  on  the  lower  end  of  the  culvert.  Reinforced  concrete 
walls,  eight  or  ten  inches  thick  make  very  satisfactory  retaining 


FARM  ENGINEERING 


^5 


walls  for  small  culverts.    They  should  have  a  solid  foundation  and 
be  well  backed  by  thoroughly  tamped  earth.     Culverts  which  are 


Plate  15.  Corrugated  steel  culvert  with  concrete  wing  walls.  The  water 
gets  no  chance  to  strike  the  embankment  as  the  walls  guide  it  into  the 
culvert.     A  very  good  installation. 

not  provided  with  wings  or  retaining  walls  are  very  likely  to  be 
washed  out  by  floods.  In  case  of  large  or  deep  culverts  the  retain- 
ing wall  should  always  be  surmounted  by  a  guard  wall  or  railing, 


Plate  16.  A  corrugated  steel  culvert  being  poorly  installed.  Notice  the 
lack  of  wing  walls.  The  large  clods  are  being  dumped  loosely  about  the 
pujivert.    The  first  heavy  rain  wjll  prpbably  wash  out  the  isulvert. 


26 


FARM  ENGINEERING 


to  prevent  teams  from  attempting  to  cross  the  ditch  rather  than 
the  culvert. 

Culvert  Not  Tamped  and  Puddled. 

It  is  a  bad  practice  to  dump  loose  dry  earth  in  beside  a  culvert 
by  means  of  a  scraper  or  shovel  unless  the  earth  be  thoroughly 
tamped.  It  is  better  not  only  to  tamp  the  earth  but  to  wet  it  as 
well.  This  "puddles"  the  soil  and  when  it  dries  it  becomes  hard 
and  solid,  not  hard  and  loose. 


Plate  17.  A  corrugated  steel  culvert  being  properly  installed.  The  concrete 
wing  walls  are  in  place  and  the  earth  is  being  tamped  and  puddled  as  it  is 
filled  in. 

The  dry,  loose  earth  crumbles  away  easily  when  subjected  to 
the  action  of  running  water,  while  the  hard  tamped  puddled  earth 
resists  the  action  of  the  water.  The  lack  of  thorough  tamping  and 
puddling  of  the  soil  about  the  culverts  often  explains  why  they 
wash  out  at  every  heavy  flood. 


PAku  engineIering 


27 


Plate  18.  An  arch  culvert  made  by  the  use  of  a  patent  steel  form.  The  log 
which  is  shown  at  the  right  should  not  be  allowed  to  remain  as  it  will  serve 
to  allow  water  to  cut  its  way  along  the  side  of  the  culvert.  Unless  this 
grade  is  built  higher,  the  culvert  will  be  subjected  to  great  strains  from 
passiirg  engines. 

SURFACES  OF  ROADS 

Now  that  we  have  taken  up  the  subject  of  road  drainage  let 
us  consider  the  matter  of  tlie  road's  surface.  A  road-  surface  must 
have  several  qualities  in  order  to  be  considered  good. 

1st.  It  must  be  hard  enough  to  prevent  the  wheels  of  passing 
vehicles  and  motors  from  cutting  into  it. 

2nd.  It  must  be  of  such  a  nature  as  to  furnish  a  "foot-hold" 
or  "grip"  for  animals  and  motors. 

3rd.     It  must  be  as  nearly  dustless  as  possible. 

4th.  It  must  be  tough  enough  that  it  will  not  crumble  under 
heavy  traffic. 

5th.     It  must  shed  water  and  dry  off  quickly  after  rains. 

6th.  It  must  be  of  such  a  nature  that  freezing  and  thawing 
will  not  ruin  it. 

7th.     It  must  not  be  too  expensive. 

The  student  will  realize  at  once  that  such  a  road  surface  is 
rather  hard  to  Und,  and  as  matter  of  fact;  the  soil  of  each  locality 


28 


FARM  ENGINEERING 


FARM  ENGINEERING 


29 


is  to  a  greater  or  less  extent  responsible  for  the  type  of  road  surface 
found  there.  This  is  true  because  the  cost  of  putting  on  some  other 
type  or  road  surface  is,  in  a  great  many  cases,  too  expensive. 

Earth  Roads. 

In  the  building  of  an  earth  road  after  it  has  been  laid  out  and 
the  part  to  be  graded  has  been  staked  out,  it  is  common  to  use  what 
is  known  as  a  "reversible  grader."  That  is,  a  grader  with  a  blade 
which  can  be  set  to  throw  the  earth  to  either  side.  If  the  soil  is 
hard  and  tough  several  furrows  may  be  plowed  on  the  lines 
where  the  ditches  will  be.  Then  with  the  grader  the  earth  is  moved 
toward  the  center  of  the  road  until  the  proper  crown  is  obtained. 
The  graders  should  be  driven  along  the  road  and  not  across  it.  The 
blade,  when  set  on  an  angle  of  about  forty-five  degrees,  pushes  the 
earth  sidewise  and  thus,  by  repeated  operations  lands  it  at  or  near 
the  center  of  the  road. 


Plate  20.  A  gasoline  road  roller  rolling  a  road  as  it  is  being  graded  by 
reversible  gTader.  This  is  an-  excellent  sclieme  for  making  a  hard  well- 
packed    road. 

The  road  should  then  be  rolled  with  a  heavy  roller.    Few  of  the 
horse  drawn  rollers  are  heavy  enough  to  accomplish  the  desired 


30 


F'ARM  ENGIN^EklMd 


result.    A  ten  to  fourteen  ton  steam  roller  is  very  satisfactory.    If 
the  soil  is, moist  at  the  time  of  rolling,  so  much  the  better. 

In  case  of  high  grades  with  deep  side  ditches,  an  elevator 
grader  is  often  used.  This  type  of  machine  is  equipped  with  a  plow 
which  throws  the  earth  upon  a  moving  apron.  The  apron  carries 
the  earth  up  to  the  desired  height  and  deposits  it  upon  the  bank. 
It  is  later  levelled  to  its  proper  position  by  the  reversible  grader. 
Such  a  bank  should  be  rolled,  and  packed  thoroughly  before  it  is 
put  into  service  as  a  road.  Otherwise  "pot  holes"  or  "chuck  holes" 
are  likely  to  form  within  a  few  days. 


Plate  21.  An  elevator  grader  or  "excavator".  This  machine  is  equipped 
v\^ith  push-cart  to  which  four  horses  are  hitched.  Such  a  machine  attached 
to  a  good  traction  engine  makes  a  very  good  rig  for  rapid  excavation. 


The  elevator  grader  if  often  used  for  the  purpose  of  loading 
dump  wagons  when  the  earth  must  be  moved  some  distance  as  in 
the  making  of  cuts  and  fills. 

Cuts  and  Fills. 

In  case  it  becomes  necessary  to  cut  down  a  portion  of  a  hill  in 
order  to  give  a  road  the  proper  grade,  it  is  usually  found  advisable 
to  move  the  earth  to  the  adjoining  low  spot  in  the  road  and  thus 
make  what  is  known  as  a  fill.  In  this  way  less  earth  needs  to  be 
moved. 


ParU  engineering^  §i 

In  case  but  little  earth  needs  to  be  moved  "slip  scrapers"  are 
Used.  These  little  scrapers  are  so  common  that  they  need  no  des- 
cription. 


Plate  22.  Fig.  1  shows  longitudinal  section  of  road  through  a  hill.  The. 
dark-shaded  portions  are  fill  and  the  light-shaded  portion  is  cut.  By  hauling 
dirt  from  a  cut  to  the  low  places  and  thus  making  the  fills  the  amount  of 
labor  was  greatly  lessened;  Fig.  2  is  a  cross  section  of  the  cut  showing 
banks  with  1  to  1  slope;  Fig.  3  is  section  of  fill  with  banks  made  2  to  1 
(8  to  4)  slope.  Note:  The  longitudinal  section  is  not  made  to  the  same 
scale  as  the  two  cross  sections. 

For  hauls  of  a  hundred  feet  or  more  it  is  common  to  use  wheel 
scrapers  or  "wheelers".  These  scrapers  are  provided  with  wheels 
and  are  so  designed  that  after  the  scraper  has  been  filled  with 
earth  it  is  raised  clear  of  the  ground  by  means  of  a  lever.  It  is  then 
hauled  to  the  desired  location  and  dumped  much  the  same  as  the 
slip  scraper.  .  i    ;  *  I 

For  long  hauls,  and  for  rapid  work  an  elevator  grader  drawn  by 
a  traction  engine  and  several  dump  wagons  drawn  by  horses  make 
an  ideal  outfit. 

Only  the  best  of  traction  engineers  and  expert  elevator  grader 
men  should  be  employed  on  such  an  outfit,  as  a  few  hours  lost  in 
"tinkering"  means  a  great  loss  of  time  and  money. 

The  side  banks  of  a  cut  should  not  be  left  perpendicular  as  such 
banks  crumble  in,  and  fill  up  the  side  ditches.  The  slope  should  be 
at  least  "one  to  one".  That  is,  they  should  recede  one  foot  to  each 
foot  in  height. 

Fills  should  slope  about  one  and  one-half  to  one  or  two  to  one. 
This  is,  they  should  recede  one  and  one-half  or  two  feet  to  each  foot 
of  rise.  The  earth  work  is  usually  figured  in  cubic  yards  of  earth 
moved.  Prices  vary  with  the  kind  of  earth,  the  length  of  haul,  and 
local  prices  of  labor,  etc. 


3^  FARM  ENGINEERINC^ 

In  case  of  hard  earth,  or  rock,  dynamite  proves  to  be  a  very 
cheap  and  efficient  excavator. 

Maintenance  of  Earth  Roads. 

The  best  method  of  caring  for  or  maintaining  the  earth  road  is 
by  the  use  of  the  King  drag  or  some  other  implement  of  like  nature. 

The  drag  consists  of  two  planks,  each  about  six  or  seven  feet 
long,  these  planks  set  upon  edge  and  are  dragged  along  the  road, 
thus  acting  as  a  pair  of  scrapers,  one  following  the  other.    The  rear 


Plate  23.  Front  view  of  a  home-made  King  drag.  The  lower  planks  are 
3"x8"x6';    top  planks  are  2"xl0"x4'. 

plank  is  about  three  feet  behind  the  front  one.  The  hitch  is  so  ar- 
ranged that  the  end  of  the  drag  nearer  the  center  of  the  road  is 
behind  the  outer  end.  Thus,  the  loose  earth  is  moved  toward  the 
middle  of  the  road.  The  right  time  to  use  a  King  drag  is  just  as  the 
mud  is  beginning  to  dry  enough  to  harden.  When  the  mud  is  thin 
and  soft  the  drag  does  little  good,  and  when  the  earth  is  dry  and 
hard  it  does  little  or  no  good. 

The  King  drag,  when  properly  used :  Fills  the  ruts,  maintains 
the  crown,  keeps  the  side  ditches  open,  and  so  puddles  and  packs 
the  soil  as  to  give  a  hard,  firm,  even  road  surface. 

In  many  rural  communities  each  farmer  drags  that  portion  of 
the  road  which  adjoins  his  farm.  Such  public  spirit  is  commend- 
able, and  profitable  as  well.  For  we  must  remember  that  "A  com- 
munity is  judged  by  the  quality  of  its  roads."  Good  roads  indicate 
that  the  community  is  up-to-date,  prosperous  and  intelligent;  bad 
roads  indicate  that  the  opposite  conditions  prevail. 

Stone  Roads. 

For  centuries  it  has  been  the  custom  to  build  roads  with  stone 
gurf^cesr    Many  roads  were  built  with  the  surfaces  of  larp  fi9,t 


FARM  ENGINEERING 


33 


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34  FARM  ENGINEERING 

stones.     Such  roads  are  unsatisfactory  for  the  following  reasons : 

They  do  not  allow  the  horses'  feet  to  secure  a  good  grip. 

When  wet  or  muddy  the  stones  are  very  slippery. 

Such  a  road  is  very  expensive. 

When  smaller  stones  are  properly  set  they  make  an  excellent 
paving  for  city  streets,  but  this  system  of  road  making  is  rarely 
found  in  country  districts  in  the  United  States. 

Macadam  Roads. 

The  term  macadam  applies  to  broken  stone  roads  which  are 
prepared  by  putting  a  thick  layer  (10  or  12  inches)  of  broken  stone 
on  the  earth  surface  of  the  road.  This  may  be  rolled  in  by  steam 
or  gasoline  rollers  or  left  to  be  rolled  down  by  traffic.  Such  roads 
are  readily  destroyed  by  a  combination  of  team  and  automobile 
traffic.  The  maintenance  of  such  a  road  under  both  team  and  auto 
traffic  is  a  hard  proposition  and  a  most  expensive  one. 

Telford  Roads. 

In  case  of  Telford  roads  a  layer  of  large  rough  stones  is  laid 
in  the  bottom  of  the  traveled  portion  of  the  road.  On  these  a  four- 
inch  layer  of  crushed  stones  is  placed  and  rolled  in  by  roller  or  by 
traffic.  This  layer  is  in  turn  covered  by  a  layer  of  fine  broken  stones 
which  is  rolled  into  the  coarser  bottom  material. 

The  macadam  and  Telford  roads,  when  made  of  a  good  tough 
wear-resisting  stone  are  very  good  for  roads  which  have  team 
traffic  only.  They  wear  well  and  the  slow-moving  vehicles  roll 
the  material,  thus  making  it  hard  and  firm.  But  when  the  auto 
with  its  soft  tire  speeds  over  the  road  at  35  to  50  miles  an  hour, 
the  maintenance  of  one  of  these  roads  becomes  a  puzzling  matter 
for  the  best  of  highway  engineers. 

NEW  TYPES  OF  ROADS. 

Had  this  book  been  written  ten  years  ago  many  pages  would 
have  been  taken  up  in  minute  directions  for  the  building  of  stone 
roads,  but  since  the  advent  of  the  automobile  the  subject  of  hard 
road  surfaces  is  a  matter  for  experiment. 

Some  authorities  took  to  petroleum  which  has  an  asphalt  base, 
as  the  solution  of  the  problem.  This  asphalt  is  worked  into  an 
earth  road  and  then  rolled.  It  gives  a  hard,  smooth  surface  which 
is  impervious  to  water.    It  do^s  not  allow  larg^e  ruts  to  form,  and 


FARM  ENGINEERING  35 

there  is  little  or  no  loose  dirt  for  the  auto  wheels  to  kick  into  the 
adjoining  fields.  Other  authorities  believe  that  the  coming  road 
will  be  made  of  concrete. 

Some  new  materials  are  now  being  used  which  form  a  soft 


Plate  25.     A  type  of  commercial  pavement  which  the  company  claims  will 
•yyithstand  teani  and  ^utoniobile  traffic, 


36  FARM  ENGINEERING 

road  surface  that  is  water-proof  and  nearly  dustless.    They  are,  as 
a  rule,  very  expensive. 

Some  companies  now  use  asphalt,  tar,  and  other  materials  for 
the  holding-  of  crushed  stone  in  place.  These  are  known  as  bitu- 
minous concretes,  or' bitrolithic  pavements.  They  are  very  ex- 
pensive and  should  be  cautiously  experimented  with.  Of  one  thing- 
we  are  certain  and  that  is  that  we  have  the  Question  of  a  good, 
cheap,  and  satisfactory  combination  tonnage  and  auto  road  to  solve.' 
We  now  have  good  roads  which  are  very  expensive,  and  cheap 
roads  which  are  not  good. 

With  the  best  efforts  of  our  high  grade  highway  engineers 
concentrated  upon  the  subject,  we  should  look  for  pretty  positive 
results  within  the  next  decade.  In  the  meantime  let  us  make  tlie 
best  possible  earth  roads  by  careful  attention  to  grading,  draining 
and  dragging  them. 

Bridges  are  now  as  much  a  commercial  article  as  are  engines, 
or  road  graders,  so  that  in  deciding  upon  a  type  of  bridge  the  engin- 
eer needs  but  to  ascertain  the  length  and  width  of  the  bridge  which 
is  needed,  and  submit  the  specifications  of  length,  width  and  maxi- 
mum load  to  the  bridge  building  firms  for  bids.  These  compani?- 
have  standard  designs  which  fit  nearly  ever}^  recjuirement,  and  as 
they  make  and  erect  the  bridges  on  a  large  scale  they  are,  as  a  rule, 
able  to  underbid  any  small  contractor. 

The  subject  of  bridge  selection  and  bridge  design  should  be 
left  to  an  engineer  who  devotes  his  whole  attention  to  the  subject 
of  bridges. 

The  day  of  wooden  bridges  is  past.  It  is  now  a  matter  of  steel 
or  concrete,  with  here  and  there  a  stone  arch. 

All  modern  highway  bridges  should  be  able  to  carry  a  moving 
load  of  twenty-five  tons  with  safety. 

ROAD   MACHINERY. 

A  few  special  points  will  be  taken  up  under  this  head  although 
many  of  the  more  important  points  have  been  brought  out  in  prev- 
ious paragraphs. 

Slip  Scrapers. 

One  of  the  simplest  of  road  machines  is  the  slip  scraper.  It 
has  been  defined  as  a  "horse  scoop."     The  scraper  should  be  pro- 


FARM  ENGINEERmG  37 

vided  with  strong,  smooth,  wood  handles,  a  rigid  steel  bail  with 
swivel,  and  a  pair  of  steel  runners  on  the  bottom  of  the  scraper. 
The  slip  is  suitable  for  moving  earth  short  distances.  It  should 
not  be  used  where  a  reversible  grader  can  be  made  to  operate. 

Wheel  Scrapers. 

Wheel  scrapers  should  be  strongly  and  simply  built.  The 
tongue  of  the  scraper  should  be  provided  with  a  loop  or  hook  to 
which  the  "snap  team"  or  "helper"  may  be  attached  during  the 
loading.  It  often  happens  that  two  horses  can,  with  little  effort, 
haul  a  load  of  earth,  which  requires  the  best  efforts  of  four  horses 
to  load. 

The  wheels  of  wheel  scrapers  are  often  made  too  light.  One 
should  always  see  to  it  that  the  scrapers  are  provided  with  strong 
wheels. 

Wheel  scrapers  are  often  used  in  hauling  earth  from  one  hun- 
dred feet  to  several  hundred  yards. 

Buck  Scrapers. 

Buck  scrapers  are  much  like  slip  scrapers  except  that  they 
have  greater  width,  and  they  are  provided  with  shoes,  so  that  as 
they  turn  over  in  dumping,  they  scatter  the  earth  over  considerable 
area  instead  of  dumping  it  in  a  pile. 

Reversible  Graders. 

A  good  reversible  grader  has  many  adjustments  which  should 
be  easily  made  by  the  operator.  A  seat  is  usually  provided  at  the 
front  of  the  grader  for  two  drivers. 

The  rear  wheels  should  be  mounted  on  extension  axles  so  that 
the  wheels  may  be  set  out  to  one  side  or  drawn  in  near  the  grader. 
By  this  means  the  wheels  are  adjusted  so  that  they  always  run  on 
hard  ground.  The  blade  should  be  adjustable  so  that  it  may  be 
made  to  throw  earth  to  either  side. 

The  two  ends  of  the  blade  should  be  supplied  with  separate 
adjustments  so  that  they  may  be  raised  or  lowered  at  will. 

Many  other  adjustments  are  found  on  up-to-date  graders, 
but  the  above  are  the  principal  ones.  The  grader  should  be  strong- 
ly built  of  steel. 

The  Elevator  Grader  (Excavator). 

The  elevator  grader  requires  a  very  great  tractive  effort  in 


gg 


Farm  engineering 


order  to  keep  moving.  For  this  reason  we  find  that  many  of  the 
best  makes  have  push  carts  attached  to  the  rear  of  the  machine. 
From  six  to  ten  horses  are  attached  in  front  and  four  or  six  are 
attached  behind.  The  rear  driver  simply  guides  his  horses  by 
means  of  a  w^heel  which  controls  the  direction  of  the  travel  of  the 
cart  wheels.  The  plow  of  the  elevator  should  be  very  strong  and 
well  braced.  The  conveyor  is  usually  made  of  a  wide  piece  of 
rubber  belting.  The  carrier  or  conveyor  should  be  adjustable  at  all 
points.  All  bearings  should  be  as  nearly  dust-proof  as  possible. 
The  bearings  should  be  equipped  with  hard  oiling  devices. 

The  Grader  Hitch. 

When  traction  engines  are  used  to  draw  reversible  or  elevator 
graders  an  adjustable  hitch  should  be  used,  by  means  of  such  a 
hitch  the  grader  may  be  steered  separately,  without  it  following 
directly  behind  the  engine. 


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>"^ss:^ 


Plate  26.  A  good  type  of  dump  wagon  showing  how  the  bottom  doors  drop 
down  to  discharge  the  load.  Beside  the  wagon  is  a  patent  steel  King  drag. 
It  is  equipped  with  lever  by  which  the  blades  may  be  set  at  any  desired 
angle.     The  picture  also  shows  how  not  to  store  road  machinery. 

Dump  Wagons. 

Good  dump  wagons  are  now  being  built  by  many  companies. 
The  front  wheels  should  be  so  hung  that  they  can  turn  at  an  angle 
of  at  least  ninety  degrees  to  the  body.    This  makes  short  turns  pos- 


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42 


FARM  ENGINEERING 


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FARM  ENGINEERING 


43 


44  FARM  ENGINEERING 

sible.  The  rear  wheels  and  axle  should  be  very  strong  as  they  must 
carry  most  of  the  load.  The  dumping  boards  or  doors  should  be 
so  hung  that  they  may  be  let  down  slowly,  for  it  often  happens  that 
it  is  desirable  to  allow  the  load  to  sift  out  over  considerable  area, 
rather  than  to  have  it  all  dumped  in  a  pile. 

Road  Rollers. 

In  general,  road  rollers  are  of  two  types,  steam  and  gasoline. 
Steam  rollers  give  good  service,  but  vv^ater  and  coal  must  be  hauled 
to  them,  and  in  many  states  a  licensed  engineer  must  be  hired. 
The  wheels  should  have  flat  tires  so  made  that  spikes  or  "grouters" 
may  be  attached  in  case  of  heavy  pulls,  or  in  case  it  is  necessary  to 
"roughen  up"  an  old  piece  of  road.  This  is  often  done  when  a  road 
surface  is  being  refinished.  The  rollers  should  be  provided  with  a 
differential  or  compensating  gear  so  as  to  make  the  drive  wheels 
each  pull  an  equal  amount,  both  on  straight  roads  and  on  curves. 

Gasoline  or  kerosene  engines  are  now  mounted  on  forms  and 
are  made  to  act  as  road  rollers.  When  they  are  built  sufficiently 
strong  and  heavy  they  make  excellent  rollers.  They  may  also  be 
used  to  operate  stone  crushers  when  standing  in  the  belt. 

Portable  Stone  Crushers. 

Some  companies  now  build  stone  crushing  plants  which  may 
be  moved  from  place  to  place,  in  the  same  way  as  threshing  ma- 
chines are  moved.  These  machines  are  operated  by  traction  en- 
gines or  road  rollers.  They  give  excellent  results  when  they  are 
operated  by  competent  men. 

All  road  machinery  should  be  stored  in  a  closed  shed.  It  should 
have  all  bright  parts  greased  when  not  in  use. 


FARM  ENGINEERING  45 

FARM  ENGINEERING— PART  III,  A. 


Farm  Cement  Work  or  Concrete  Construction. 

Each  year  sees  the  structures  of  the  farms  being  made  les:--  of 
wood  and  other  materials  which  do  not  possess  the  quahty  of  great 
durability. 

Concrete  is  rapidly  taking  the  place  of  wood  in  our  farm  struc- 
tures, and  it  is  fitting  that  we.  give  the  subject  of  concrete  con- 
strviction  careful  attention. 

Cement. 

We  have  two  general  classes  of  cement:  Natural  and  Port- 
land. In  the  natural  cement  the  "cement  rock"  is  used  as  it  comes 
from  the  earth.  It  is  simply  converted  into  cement  by  a  baking  and 
grinding  method.  Now  if  the  cement  rock  happens  to  be  good  the 
resultant  cement  will  be  good,  and  if  the  rock  is  bad  the  cement  will 
also  be  bad.  For  this  reason  natural  cement  is  generally  considered 
to  be  unreliable.  It  is,  as  a  rule,  slightly  cheaper  than  Portland 
cement.  Portland  cement  is  made  of  chemically  analyzed  rocks 
mechanically  mixed  in  chemically  correct  proportions.  This  ren- 
ders the  strength  and  setting  qualities  of  good  grades  of  Portland 
cement  very  uniform. 

(Some  people  foolishly  believe  that  Portland  cement  is  made 
in  Portland,  Maine  or  Oregon.  The  name  refers  to  the  process,  not 
to  the  city  where  it  is  made.) 

Setting  of  Cement. 

When  cement  sets  the  powdered  rock  takes  up  its  water  of 
crystallization  and  again  becomes  a  stone.  It  adheres  to  the  sand 
or  stone  which  it  touches  and  then  we  get  concrete.  There  are  some 
intricate  chemical  processes  in  the  setting  of  cement,  but  if  we  re- 
member that  cement  work  must  be  kept  moist  while  setting  and 
that  the  setting  process  continues  for  several  weeks,  w5  will  have 
the  main  part  of  the  practical  side  of  the  process  in  hand. 

Cement  and  Concrete. 

When  we  speak  of  cement  work  we  refer  to  a  cement  and  sand 
mixture  which  is  free  from  gravel  or  broken  stone.  Thus,  when  we 
say  a  post  is  made  of  a  one,  three  mixture,  we  mean  that  one  part 


46 


FARM  ENGINEERING 


FARM  ENGINEERING  4t 

by  measure  of  cement  has  been  added  to  three  equal  parts  of  sand. 
In  speaking  of  concrete  we  refer  to  the  mixture  as  1,  2,  2  or  1,  2^, 
2^,  or  1,  3,  3,  etc.  Thus,  we  mean  that  one  part  of  cement  has 
been  added  to  two  parts  of  sand  and  two  parts  of  stone  (all  propor- 
tions by  measure,  not  by  weight.) 

Thus  the  first  number  indicates  cement,  the  second  sand,  and 
the  third  gravel  or  broken  stone. 

Sand. 

Sand  for  good  cement  or  concrete  work  should  be  free  from 
dirt,  sticks,  leaves,  etc.  It  should  have  sharp  angular  grains,  not 
smooth  rounded  particles. 

Gravel. 

Gravel  should  be  clean  and  angular.  Smooth  glassy  pebbles 
usually  make  poor  concrete. 

Broken  Stone. 

Crushed  stone  is  generally  much  better  for  concrete  than 
gravel,  as  the  particles  are  rough  and  freshly  broken  the  cement 
gets  a  better  grip  on  them  than  on  smooth  gravel. 

Proportion  to  Use. 

Neat  Cement  is  used  for  the  purpose  of  giving  water-proof 
coatings  to  cement  or  concrete  work.  Neat  cement  is  pure  cement 
as  it  comes  from  the  sack.  It  is  mixed  with  water  and  applied  as 
a  paint  or  wash  to  the  surfaces  of  walls,  etc.,  for  the  purpose  of 
filling  the  pores  of  the  cement  or  concrete.  It  does  the  work  very 
well  when  properly  applied. 

A  1-3  mixture  is  a  very  rich  mixture.  It  is  used  for  the  purpose 
of  making  cement  fence  posts,  and  for  top-coating  cement  floors, 
sidewalks,  etc. 

A  1-4  mixture  is  used  for  the  building  of  posts,  troughs,  side- 
walks, floors,  engine  bases,  sills,  etc. 

A  1-5  mixture  is  not  very  desirable  as  it  could  be  greatly 
strengthened  by  substituting  some  gravel  or  broken  stone  for  part 
of  the  sand. 

A  1,  2,  2,  mixture  makes  a  very  strong  concrete,  suitable  for 
almost  any  kind  of  work  which  requires  a  dense,  hard  concrete. 

A  1,  21^,  2y2,  mixture  is  also  strong  and  hard.  It  is  used  for 
the  building  of  silos,  walls,  floors  and  side  walks,  but  care  should  be 


48 


FARM  ENGINEERING 


taken  to  give  the  walks  and  floors  a  top  dressing  of  1-3  cement 
mixrare.  This  top  dressing  should  be  from  one-half  to  one  inch 
thick.  It  should  be  applied  immediately  after  the  body  of  the  floor 
is  laid. 

1,  3,  3  mixtures  and  1,  3^,  3^  mixtures  are  often  used  for  the 
building  of  walls,  blocks  and  side-walks,  but  it  is  a  practice  of 
doubtful  economy  to  use  a  mixture  weaker  than  1,  3,  3  for  farm 
purposes. 

Mixing  Cement  or  Concrete, 

Proportioning.  It  is  common  to  measure  out  the  cement,  sand 
and  gravel  in  boxes  or  pails,  so  as  to  get  the  right  proportions. 
Thus  we  use  one  box  cement,  three  boxes  sand  and  three  boxes 
gravel  for  a  1,  3,  3  mixture. 

Now  we  do  not  get  seven  boxes  of  concrete,  because  the  sand 
settles  in  among  the  gravel,  and  the  fine  cement  sifts  in  among  the 
sand  and  gravel.  Thus  when  the  setting  is  complete  we  get  a 
solid  rock. 

One  aiithority  has  computed  the  amounts  of  cement,  sand  and 
stone  necessary  to  make  a  yard  of  rammed  concrete  as  follows : 


Mixtures 


Aoiounts 


-1.9 

a 

-a 

a 

a 

eS 

o 

0) 

CO 

OS 

o 

atone 
1  inch  and  under 


1 

2.( 

4.0 

1 

2.5 

5.0 

1 

3.0 

5.0 

Stone 
2i  inch  and  under 


1 

2.0 

4.0 

1 

2.5 

5  0 

1 

3.0 

5.0) 

□9 

cc 

00 

t: 

'O 

JD 

>j 

p»l 

X3 

D 

d 

*s 

o 

o 

a 

tS 

03 

a 

0) 

a 

o 

o 

o3 

jj 

OS 

CO 

Clean 
Materials 


1 

4H 

0.44 

0.89 

1 

19 

0.46 

0.91 

1 

11 

0.5] 

0.86 

Clean 
Materials 


1 

48 

0.45 

0.91) 

1 

21 

0.46 

0  92 

1 

14 

0.52 

0.87 

FARM  ENGINEERING 


49 


Mixing. 

Hand  mixing-  is  very  common  in  farm  practice.     The  gravel 
and  sand  are  spread  upon  a  large  board  platform  and  then  the  ce- 


Plate  33.  At  the  top  is  shown  a  home-made  concrete  mixer  at  work.  The 
engine  is  geared  by  jack-shaft  and  rope-belt  to  the  square  box.  The  right 
amount  of  sand,  cement  and  gravel  is  put  in  the  box,  the  lid  is  put  on,  and 
the  box  is  then  revolved.  When  the  dry  mixing  is  complete,  the  water  is 
added  through  the  axle  which  is  a  pipe  with  perforated  bottom.  When 
the  wet  mixing  is  complete,  the  clutch  is  released,  the  lid  of  the  box  is 
loosened  and  raised  to  the  position  shown  in  the  bottom  picture.  The  con- 
crete is  then  dumped  by  revolving  box  one-half  turn.  Two  men  can  thor- 
oughly mix  a  yard  per  hour  with  this  simple  machine,     It  costs  about  $6.00, 


50  ,    FARM  ENGINEERING 

ment  is  spread  over  the  pile  of  sand  and  gravel.    The  whole  is  "dry- 
mixed"  twice  by  shoveling  from  one  part  of  the  platform  to  the 
other.    Water  is  then  added  and  the  whole  mass  is  wet  mixed  two 
or  three  times  by  thoroughly  shoveling  it. 
Machine  Mixing. 

Batch  mixers  are  very  popular  because  the  right  proportions 
of  cement,  sand  and  gravel  are  thrown  into  a  steel  box,  and  this 
is  revolved  until  the  material  is  thoroughly  dry  mixed.  Then 
water  is  added  while  the  machine  is  in  motion  and  the  wet  mixing 
is  done  without  trouble.  The  whole  is  then  dumped  to  the  floor 
or  to  a  waiting  wheel-barrow. 

Continuous  Mixers. 

Continuous  mixers  are  so  built  that  the  right  amounts  of  ce- 
ment, sand  and  gravel  are  continually  dropped  into  the  mixing 
drum  or  trough.  The  material  is  dry  mixed  at  one  end  of  the  drum 
or  trough  and  as  it  is  moved  to  the  other  end  water  is  added. 

Unless  these  mixers  are  used  by  careful  workmen  there  is 
likely  to  be  an  uneven  proportioning  of  the  mixture  due  to  clogging 
of  one  of  the  feeding  devices. 

Should  the  cement  feed  remain  clogged  for  any  great  length  of 
time  the  resultant  concrete  would  be  a  mixture  of  sand,  gravel  and 
water.  Thus  a  whole  job  of  concrete  work  may  be  spoiled  by  one 
minute's  carelessness  on  the  part  of  the  operator. 

Reinforced  Concrete. 

When  concrete  work  is  subjected  to  bending  stresses,  as  in  the 
case  of  fence  posts  or  beams  the  side  of  the  member  which  is  sub- 
jected to  tension  should  be  reinforced  with  steel  or  iron  wires  or 
roughened  rods. 

This  is  done  because  cement  or  concrete  is  very  strong  in  com- 
pression, but  it  is  rather  weak  in  tension. 

For  flat  slabs  such  as  the  sides  of  tanks,  arch  culverts,  etc., 
a  piece  of  heavy  woven  wire  fence  makes  excellent  reinforcing 
material. 

For  such  pieces  of  work  as  fence  posts,  roller  wheels,  engine 
bases,  etc.,  barbed  fence  wire  is  very  good. 

In  case  a  lot  of  old  barbed  wire  is  available,  it  is  possible  to 
twist  two  or  more  strands  together  to  make  a  rough,  wire  cable. 
This,  when  twisted,  is  straight  and  strong. 


FARM  ENGINEERING  51 

The  twisting  process  is  easily  accomplished  by  twisting  the 
ends  of  wires  about  the  spokes  of  a  wagon  wheel  and  the  other 
end  to  a  post.  Raise  the  wagon  wheel  from  the  ground  and 
turn  it  until  the  wires  are  tightly  twisted  into  a  cable.  If  the 
wires  are  kept  tight  while  the  twisting  is  being  done  the  resultant 
cable  will  be  straight,  and  therefore  easily  placed  in  any  type  of 
cement  or  concrete  work.  Cables  are  often  made  as  much  as  200 
to  300  feet  long  and  then  cut  up  into  pieces  of  desired  length.  This 
provides  an  excellent  wa}'-  of  getting  some  desirable  service  out  of 
old  barbed  wire. 
Dry  Mixtures. 

When  we  add  but  sufficient  water  to  moisten  the  cement  or 
concrete  we  speak  of  it  as  a  dry  mixture.  Such  a  mixture  may  be 
tamped  into  a  mold  and  the  mold  may  be  immediately  removed. 
While  this  is  a  desirable  feature,  yet  it  is  more  than  offset  by  the 
fact  that  such  cement  or  concrete  is  nearly  always  very  porous. 

As  these  porous  concretes  permit  water  to  soak  through  very 
readily  they  are  not  very  desirable  for  tanks,  floors,  etc.  When 
alkali  is  present  in  the  water  they  are  very  readily  destroyed,  as 
the  alkali  water  gets  all  through  the  concrete  and  causes  it  to  dis- 
integrate. 
Wet  Mixture. 

When  sufficient  water  is  added  to  concrete  to  cause  it  to  flow 
from  the  shovel  like  soft  batter  it  is  said  to  be  a  wet  mixture.  This 
type  of  mixture  forms  a  hard  and  dense  concrete  which  will,  when 
properly  made,  be  nearly  water-proof. 

As  the  wet  mixture  will  not  stand  up  when  placed  in  the  molds, 
it  becomes  necessary  to  leave  the  molds  in  place  for  some  time. 
The  molds  may  be  removed  as  soon  as  the  work  is  hard  enough 
to  stand,  but  it  is  better  to  leave  them  on  for  a  week  at  least. 

As  the  wet  mixture  is  being  poured  into  the  molds  it  is  well  to 
move  the  large  pebbles  back  from  the  sides  of  the  molds  by  means 
of  a  flat  shovel  or  a  crowder.  The  crowder  is  nothing  more  than 
a  large  hoe  with  the  goose  neck  straightened  out. 

As  the  shovel  or  crowder  pushes  back  the  large  stones  or 
gravel,  water  carrying  sand  and  cement  rushes  in  between  the  wall 
and  the  shovel.  Thus  a  coating  of  cement  and  sand  is  given  to 
the  concrete  work.  This  improves  its  appearance  and  at  the  same 
time  renders  it  more  nearly  water-proof. 


52  FARM  ENGINEERING 

Silos. 

Silos  are  built  of  monolithic  cement  work,  of  monolithic  con- 
crete and  of  cement  blocks.  In  all  cases  they  must  be  strongly  re- 
inforced.    See  Atlas  Portland  Cement  Bulletin. 

Houses. 

The  foundations  for  houses  are  often  made  of  solid  concrete 
while  the  portions  of  the  walls  above  the  foundation  are  made  of 
cement  blocks,  laid  up  like  stones  or  bricks.  Unless  the  blocks  are 
made  of  a  rich  mixture  they  absorb  water  readily.  This  often 
causes  the  walls  of  cement  houses  to  be  damp  and  unhealthy. 

Sidewalks. 

In  building-  a  side-walk  we  use  about  four  inches  of  1,  3,  3 
mixture  and  put  on  a  top  dressing  of  about  ^-2  inch  of  1,  2  or  1,  3 
mixture. 

The  side  walk  should  be  made  in  sections  not  more  than  five 
feet  long.  The  edge  of  one  section  should  be  greased  with  oil  or 
axle  grease  before  the  other  section  is  laid.  In  this  way  the  joint 
forms  a  line  of  cleavage,  or  what  is  known  as  an  "expansion  joint." 
This  joint  becomes  small  in  summer  as  the  walk  expands,  and  wide 
in  winter  when  the  walk  contracts. 

Concrete  Floors. 

The  floors  are  made  the  same  as  walks  but  the  blocks  may  be 
as  large  as  10  feet  square.  ^     ,.j  \ 


Plate  34.  A  very  desirable  hog  trough  can  be  made  of  cement.  This  trough 
cost  90  cents  and  labor.  The  trough  weighs  about  450  pounds.  It  is  need- 
less to  say  that  the  hogs  do  not  root  it  over. 


FARM  ENGINEERING 


5a 


Fence  Posts. 

Strong  durable  fence  posts  can  be  made  by  the  use  of  a  wet 
1-3  mixture  in  molds  which  make  line  posts  not  less  than  five  inches 
square  and  corner  posts  not  less  than  eight  inches  square  at  the 
ground  line. 

The  line  posts  should  be  reinforced  by  two  strands  of  barbed 
wire  in  each  corner  while  the  corner  posts  should  have  not  less  than 
six  strands  in  each  corner. 

Pig  Troughs. 

Pig  troughs  should  be  made  with  the  insides  sloping  outward 
in  order  to  make  it  easy  for  the  pig  to  drink,  and  in  order  to  pre- 
vent the  ice  which  may  form  in  the  trough  from  breaking  the  sides 
of  the  trough.    Pig  troughs  should  be  well  reinforced. 


Plate  35.  A  concrete  watering  trough  made  of  2,  2^,  2^.  The  mixture 
was  poured  in  the  moulds  and  all  coarse  material  worked  back  from  the 
surface  by  means  of  a  grader.  Sixteen  pounds  of  reinforcing  wire  was  used 
in  the  tank.  It  stood  filled  with  water  for  three  seasons  during  winter 
and  summer.  At  times  the  mercury  fell  to  29  below  zero,  but  the  trough 
showed  no  signs  of  giving  way..  The  inside  walls  of  the  tank  slope  out- 
ward as  they  approach  the  top,  thus  preventing  the  ice  from  bursting  them. 

Large  Troughs. 

Large  troughs,  for  cattle  and  horses  may  be  made  with  walls 
six  or  more  inches  thick  at  the  top.  The  walls  should  become 
thicker  toward  the  bottom  of  the  trough  so  that  the  inside  of  the 
trough  slopes  outward  toward  the  top.     This  prevents  ice  from 


54 


FARM  ENGINEERING 


breaking-  the  sides  of  the  tank.  The  ends,  sides  and  bottoms  of  all 
tanks  should  be  strongly  reinforced.  All  sharp  angles  should  be 
rounded  or  filleted,  as  cement  work  usually  cracks  from  some  sharp 
internal  angfle. 


mmMmim^ssmmm^SM^mmm 


Plate  36.  Cross  section  of  a  watering  trough  showing,  "a",  sloping  internal 
side  walls;  "b",  filleted  or  rounded  corners  or  angles;  "c",  the  placing  of 
reinforcing  wires.  The  large  dots  represent  the  ends  of  the  side  and  bottom 
wires.  The  position  of  the  wires  which  reach  from  the  top  at  one  side 
around  the  bottom  and  up  to  the  top  at  the  other  side,  is  also  shown. 


Plate  37.  Very  desirable  land  rollers  are  now  being  made  by  casting  cement 
wheels  in  patent  rims.  The  rims  remain  on  the  wheels  and  form  a  steel 
tire  for  them.  These  rollers  are  heavy,  but  due  to  the  fact  that  the  weight 
is  in  the  wheels,  they  are  not  very  hard  to  pull. 


FARM  ENGINEERING 


55 


Plate  38.  Cement  contractor's  yard  where  cement  tiles  are  being  con- 
structed by  pouring  the  cement  in  tile  moulds.  These  tiles  are  hard  and 
almost  impervious  to  moisture. 

The  field  of  farm  cement  construction  is  spreading  daily,  and 
the  ingenious  farmer  may  make  nearly  any  of  the  farm  buildings  of 
concrete  if  he  but  applies  his  ingenuity  to  the  task. 


Examination 


Note  to  Student — These  questions  are  to  be  answered  inde- 
pendently. Never  consult  the  text  after  beginning  your  examina- 
tion. Use  thin  white  paper  about  6x9  in.  for  the  examination. 
Number  the  answers  the  same  as  the  questions,  but  never  repeat 
the  question.     Mail  answers  promptly  when  completed. 


1 — Explain  how  the  automobile  affects  the  old  types  of  road  sur- 
faces. 

2 — What  is  axle  friction  of  vehicles? 

3 — Tell  how  the  hardness  of  a  road  surface  afifects  the  rolling 
friction, 

4 — Why  is  the  pull  required  to  move  a  vehicle  not  exactly  propor- 
tional to  the  grade? 
5 — How  may  we  drain  roads  which  run  along  side  hills? 


56  FARM  ENGINEERING 

6 — Why  is  the  "arch  type"  of  stone  or  concrete  culvert  superior  to 

the  "box  type"? 
7 — Of  what  use  are  wing  walls  when  used  with  culverts? 
8 — Tell  how  to  set  a  corrugated  steel  culvert  properly. 
9 — What  qualities  must  a  road  surface  have  if  it  is  to  be  considered 
as  good? 

10 — Tell  how  to  grade  a  road  with  a  reversible  grader. 

11 — Tell  how  and  in  what  cases  elevator  graders  are  used. 

12 — Tell  under  what  conditions  wheel  scrapers  are  used. 

13 — What  is  the  object  of  rolling  a  new  road  surface? 

14 — How  heavy  should  a  good  road  roller  be? 

15 — Why  should  the  banks  of  cuts  and  fills  be  sloping? 

16 — Tell  how  to  maintain  the  surface  of  an  earth  road. 

17 — What  is  a  King  drag?    How  is  it  used? 

18 — What  adjustments  should  we  look  for  in  a  good  reversible 
grader? 

19 — Tell  some  of  the  good  points  to  be  looked  for  in  an  up-to-date 
road  roller. 

20 — What  is  Portland  Cement? 

21 — AVhat  is  meant  by  1,  3  mixture? 

22 — What  is  meant  by  a  1,  3,  3  mixture? 

23 — What  kind  of  sand  and  gravel  should  we  select  for  concrete 
work? 

24 — Tell  how  to  properly  mix  a  batch  of  concrete. 

25 — Tell  how  to  build  troughs  in  such  shape  as  to  prevent  the  freez- 
ing of  water  in  the  trough  from  bursting  it. 


Write  This  at  the  End  of  Your  Examination. 

I  hereby  certify  that  the  above  questions  were  answered  entirely 
by  me. 

Signed 

Address  


r 


B=ll— II 6)@ It— H= 


gen IB 


^  Correspondence  College 
of  Agriculture 


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FARM    ENGINEERING—PART   ONE 


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